Rock Art Research in the Digital Era: Case Studies from the 20th International Rock Art Congress IFRAO 2018, Valcamonica (Italy) 9781407360119, 9781407360126

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Rock Art Research in the Digital Era

L E A IN N L IO ON IT D L D IA A ER AT

A R C HA E O L O G Y O F P R E H I S T O R I C A RT

M

VO LU M E 5

Case Studies from the 20th International Rock Art Congress IFRAO 2018, Valcamonica (Italy) EDITED BY

M I G U E L C A R R E R O - P A Z O S, R E B E C C A D Ö H L , J U L I A N J A N S E N VA N R E N S B U R G , P A O L O M E D I C I , A L I A VÁ Z Q U E Z - M A R T Í N E Z

BA R I N T E R NAT I O NA L S E R I E S 3 0 9 8

VO LU M E 5

A R C HA E O L O G Y O F P R E H I S T O R I C A RT

Rock Art Research in the Digital Era Case Studies from the 20th International Rock Art Congress IFRAO 2018, Valcamonica (Italy) EDITED BY

M I G U E L C A R R E R O - P A Z O S, R E B E C C A D Ö H L , J U L I A N J A N S E N VA N R E N S B U R G , P A O L O M E D I C I, A L I A VÁ Z Q U E Z - M A R T Í N E Z

BA R I N T E R NAT I O NA L S E R I E S 3 0 9 8

Published in 2022 by BAR Publishing, Oxford BAR International Series 3098 Archaeology of Prehistoric Art, Volume 5 Rock Art Research in the Digital Era isbn isbn doi

978 1 4073 6011 9 paperback 978 1 4073 6012 6 e-format

https://doi.org/10.30861/9781407360119

A catalogue record for this book is available from the British Library © the editors and contributors severally 2022 3D model of Laxe dos Carballos (Campo Lameiro, Galicia, Spain), by Alia Vázquez-Martínez cover image

The Authors’ moral rights under the 1988 UK Copyright, Designs and Patents Act, are hereby expressly asserted. All rights reserved. No part of this work may be copied, reproduced, stored, sold, distributed, scanned, saved in any form of digital format or transmitted in any form digitally, without the written permission of the Publisher. Links to third party websites are provided by BAR Publishing in good faith and for information only. BAR Publishing disclaims any responsibility for the materials contained in any third party website referenced in this work.

BAR titles are available from: BAR Publishing 122 Banbury Rd, Oxford, OX2 7BP, UK [email protected] www.barpublishing.com

ARCHAEOLOGY OF PREHISTORIC ART Series Editors: Andrew Meirion Jones, University of Southampton, UK and Ing-Marie Back Danielsson, Uppsala University, Sweden

This series was initiated in 2017 in response to a renaissance in research activity in archaeology of art, specifically the field of prehistoric art. Several major research projects, high profile exhibitions, and conferences have been devoted to the topic in recent years. The launch of this new series reflects the renewed interest in the archaeology of prehistoric art. One consequence of the intense scholarly interest is that the theoretical and methodological approach to prehistoric art underwent a sea change over the last ten years. The Editors of this timely series encourage contributions that take a fresh approach to prehistoric art (particularly new materialist or post-humanist perspectives) and new methodological or scientific approaches to the analysis of art (especially new digital methods, or new methods of dating). Having said this, high-quality contributions of all theoretical and methodological kinds are considered. The geographical scope of the series is global, and contributions are encouraged from all regions of the world. If you are interested in publishing in the Archaeology of Prehistoric Art series, please contact: [email protected]

Editorial Advisory Board Ben Alberti, Framingham College, USA Lara Bacelar Alves, Coimbra University, Portugal Marta Díaz-Guardamino, Durham University, UK Fredrik Fahlander, Stockholm University, Sweden Ingrid Fuglestvedt, Oslo University, Norway Dragoş Gheorghiu, National University of Arts, Bucharest, Romania Joakim Goldhahn, Linneaus University, Sweden/Griffith University, Australia Simon Kaner, University of East Anglia, UK Antti Lahelma, University of Helsinki, Finland Jo McDonald, University of Western Australia, Australia David Morris, McGregor Museum & Sol Plaatje University, Kimberley, South Africa Stratos Nanoglou, Hellenic Ministry of Culture and Sports, Athens, Greece Courtney Nimura, University of Oxford, UK Elisabeth Arwill Nordbladh, Gothenburg University, Sweden David Pearce, University of Witwatersand, RSA Guillaume Robin, University of Edinburgh, UK David Robinson, University of Central Lancashire, UK Ylva Sjöstrand, Uppsala University, Sweden

Titles in the series Design and Connectivity The case of Atlantic Rock Art Joana Valdez-Tullett BAR International Series 2932 | 2018

Volume 1

Rock Art, Water, and Ancestors The semiotic construction of a sacred landscape in the central Andes (1800 BCE - CE 1820) Gordon Ambrosino BAR International Series 2969 | 2020

Volume 2

Arts and Crafts in Iron Age East Yorkshire A holistic approach to pattern and purpose, c. 400BC-AD100 Helen Chittock BAR British Series 660 | 2020

Volume 3

Change and Continuity in the Prehistoric Rock Art of East Siberia An archaeological and anthropological exploration into ethno-cultural identity, belonging, and symbolism Irina A. Ponomareva BAR International Series 3057 | 2021

Volume 4

Rock Art Research in the Digital Era Case Studies from the 20th International Rock Art Congress IFRAO 2018, Valcamonica (Italy) Edited by Miguel Carrero-Pazos, Rebecca Döhl, Julian Jansen van Rensburg, Paolo Medici, Alia Vázquez-Martínez BAR International Series 3098 | 2022

Volume 5

Of Related Interest Rock Art in the Landscapes of Motion Proceedings of a session of the 20th International Rock Art Congress IFRAO 2018 in Valcamonica, Italy Edited by Pawel L Polkowski and Frank Förster BAR International / British Series 3092 | 2022 Change and Continuity in the Prehistoric Rock Art of East Siberia An archaeological and anthropological exploration into ethno-cultural identity, belonging, and symbolism Irina A. Ponomareva BAR International Series 3057 | 2021 Carved in Stone The archaeology of rock-cut sites and stone quarries Edited by Claudia Sciuto, Anaïs Lamesa, Katy Whitaker and Ali Yamaç BAR International Series 3054 | 2021 ¡El Yunque se levanta! Interdisciplinarity and activism at the La Mina petroglyph site Rhianna C. Rogers, James Schuetz and Rex Cauldwell BAR International Series 3019 | 2021 Shepherds Who Write Pastoral graffiti in the uplands of Europe from prehistory to the modern age Edited by Marta Bazzanella and Giovanni Kezich BAR International Series 2999 | 2020 Drawn and Written in Stone An inventory of stepped structures and inscriptions on rock surfaces in Upper Tibet (ca. 100 BCE to 1400 CE) John Vincent Bellezza BAR International Series 2995 | 2020 Design and Connectivity The Case of Atlantic Rock Art Joana Valdez-Tullett BAR International Series 2932 | 2019

For more information, or to purchase these titles, please visit www.barpublishing.com

Contents Contributors....................................................................................................................................................................... viii Abstract.............................................................................................................................................................................. xiii

Introduction.................................................................................................................................................................. 1 Miguel Carrero-Pazos, Rebecca Döhl, Julian Jansen van Rensburg, Paolo Medici, Alia Vázquez-Martínez

1. The Arara Vermelha Rock Shelter, Roraima, Brazil: perspectives Concerning Amazonian Sheltered Petroglyphs.................................................................................................................................................. 7 Marta Sara Cavallini, Raoni BM Valle, Filippo Stampanoni Bassi, Claide de Paula Moraes, Márcio Amaral, Carlos Augusto Palheta Barbosa, Marcos Eugênio Brito de Castro, Rogério Andrade, Manoel Fabiano da Silva Santos, Jaime Xamen Wai Wai, Levemilson Mendonça “Lei’’ da Silva, Miguel Espino Villarreal 2. Phantoms on granite: evidence of Iron Age engravings in Western Galicia (NW Iberia).................................. 25 Alexandre Paz-Camaño, Xavier Barros Pereira, Vanesa Mariño Calvo, Eloy Martínez Soto 3. The prehistoric open-air sanctuary of Penedo do Ferro (Monforte, Portugal)................................................... 37 Leonor Rocha, Paula Morgado 4. Neolithic image, symmetry and context: challenges in montane stone from Cumbria, U.K.............................. 45 Steve Dickinson 5. New technologies for the survey, documentation and representation of rock art remains................................. 53 Gianni Furiassi 6. Digital documentation of Ancestral Pueblo and Ute rock art in the Canyons of the Ancients National Monument, Colorado (USA)..................................................................................................................... 63 Radosław Palonka, Bolesław Zych 7. Close encounters of the third dimension: recording the three-dimensionality of the “topographic representations” in the prehistoric rock art of Valcamonica and Valtellina (Italy)............................................ 81 Angelo Martinotti, Alberto Marretta 8. New digital insights over the Domus de Janas with paintings: some case studies............................................... 95 Giuseppa Tanda, Carla Mannu 9. More than meets the eye. Structured light and 3D enhancing strategies: the case of the Assa Valley rock art (Vicenza, Italy)............................................................................................................................... 107 Cinzia Bettineschi, Luigi Magnini, Emanuela Faresin, Laura Burigana, Armando De Guio, Giuseppe Salemi 10. Rock art superimpositions in Cerro de los Indios 1 (Santa Cruz, Argentina): unravelling the sequence using digital technologies........................................................................................................................ 123 Agustina Papú 11. The site of Nag el-Hamdulab in 360°: an alternative way to experience a story from the past....................... 135 Alberto Urcia, Alessia Brucato, Maria C. Gatto, Antonio Curci

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Contributors Editors

Alia Vázquez Martínez (University of Santiago de Compostela/University of Alcalá, Spain)

Miguel Carrero-Pazos (University of Oviedo, Spain)

Postdoctoral researcher at the University of Santiago de Compostela (USC), and currently with a Margarita Salas contract at the University of Alcalá (UAH). She is a specialist in the application of computer techniques for the documentation and study of rock art in Northwestern Iberia. Her previous studies allowed her to create some of the most complete rock art databases currently available in Galicia (GEPN-AAT, University of Santiago de Compostela). These repositories are essential both for the study and documentation of a set of very delicate sites in terms of their conservation (e.g. the Galician petroglyphs), and for making heritage decisions with contrasted data. Her research stay at the University of Alcalá focuses on the documentation of rock engravings with photogrammetric techniques and the development of databases in other Iberian territories.

Lecturer in Prehistory at the University of Oviedo. Specialist in computationally informed landscape archaeology, his research focuses on the application of GIS and spatial statistics to model monumental landscapes. He is also interested in 3D imaging techniques and the application of computer tools for the study and 3D analysis of rock art engravings and Roman inscriptions. Rebecca Döhl (Humboldt University of Berlin, Germany) Archaeologist and Egyptologist (PhD), lecturer at the Institute of Archaeology - Archaeology and Cultural History of Northeast Africa, specialised in rock art research, landscape archaeology, GIS, 3D photogrammetry, Digital Humanities. Field director of rock art survey in Wadi Berber, Egypt (2010-2017, German Archaeological Institute, Cairo). Since 2016 project coordinator for Corpus of Ancient Egyptian Multimodal Communication (Humboldt University of Berlin).

Authors Márcio Amaral (Institute for Sustainable Development Mamirauá, Brazil)

Julian Jansen van Rensburg (Paleowest, Phoenix, United States)

He has a bachelor degree in Archeology from the Archaeology and Anthropology Program at the Federal University of Western Pará (UFOPA), senior technician in archaeology at the archaeology laboratory of IDSM Institute for Sustainable Development Mamirauá, linked to the Research Group on Archaeology and Cultural Heritage Management in the Amazon.

Dr Julian Jansen van Rensburg has 22 years of experience in archaeological heritage projects throughout the world and is currently a Senior Principal Investigator at Paleowest. His main focus of research is in the Middle East and has worked extensively on the island of Soqotra where he has led numerous research projects and two National Geographic expeditions to examine rock art. During these expeditions he has developed a range of techniques to record parietal and open-air petroglyph rock art sites. He has also worked in close collaboration with local Soqotra people and government officials to develop heritage awareness activities and establish protection measures for rock art sites on Soqotra.

Rogério Andrade (Federal University of Western Pará (UFOPA), Brazil) Archaeologist, he had his bachelor degree in Archaeology from the Federal University of Western Pará (UFOPA). He developed a monograph in the archaeology of the Santarém area. He is working with contract archaeology in several parts of Brazil. He was an invaluable field assistant and excavator during the 2014 excavation campaign at the Arara Vermelha site.

Paolo Medici (Centro Camuno di Studi Preistorici, Italy) He has a PhD in Egyptology and works as archaeologist as Excavation Director at the Centro Camuno di Studi Preistorici since 2010. He participated in several interdisciplinary projects for the technological advancement in archaeological research and documentation. In 2020, he also founded the association ArchExperience, focused on experimental archaeology, and since September 2021, the association manages the archaeological site and museum of the Riserva Naturale delle Incisioni Rupestri di Ceto, Cimbergo e Paspardo.

Xavier Barros Pereira (University of Vigo, Spain) Geosciences and Geological Heritage specialist, University of Vigo, Spain. Graduate in Mine Engineering with specialisation in Geology and Environment. Currently high school´s Science teacher and manager in Olho de Sapo Geocultural Services for geologic dissemination activities.

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Contributors Cinzia Bettineschi (University Augsburg, Germany)

Antonio Curci (University of Bologna, Italy)

Cinzia Bettineschi (PhD) is Lecturer and Associate Researcher in Archaeology at the University of Augsburg (Germany). Her main expertise lies in craft productions, ancient technology, and in digital applications for landscape studies. Since 2021, she is also a member of the directive board of the Centro Camuno di Studi Presitorici. Author or co-author of more than 40 scientific publications, including 2 edited volumes.

Antonio Curci is Associate Professor at the University of Bologna, co-director of the Aswan-Kom Ombo Archaeological Project (AKAP-Egypt). He is scientific responsible for ArcheoLaBio-Bioarchaeological Research Centre, with archaeozoological research activities and participation in projects led by the Department of History and Cultures in Italy and other countries. His research areas also include methods of archaeological documentation, 3D survey and relief, cultural heritage conservation and enhancement.

Marcos Eugênio Brito de Castro (Independent researcher and freelance consultant)

Manoel Fabiano da Silva Santos (Federal University of Western Pará (UFOPA), Brazil)

Experimented field archaeologist specialised in archaeological topography with undergraduate degree in Civil Engineering. He has been contributing to several archaeological research with topography, surveying, excavations and drawings of archaeological material. He was the first topographer to reach the site in 2008 producing the fundamental topographic map of the Arara Vermelha.

Archaeologist, he had his bachelor degree in archaeology from Federal University of Western Pará (UFOPA). He developed a monograph on archaeobotanical analysis of materials from Santarém sites. He is working with contract archaeology throughout Northern Brazil. He was an invaluable field assistant and excavator during the 2014 excavation campaign at the Arara Vermelha site.

Alessia Brucato (University of Bologna, Italy)

Armando De Guio (Department of Cultural Heritage: Archaeology and History of Art, Cinema and Music, University of Padua, Italy)

Archaeologist devoted to the study of the Near-Eastern Prehistory and Protohistory. She participates in research teams in Italy, the United States, Egypt and Ethiopia as Supervisor, Topographer and Photogrammetry Specialist. Her work focuses on 3D modelling, data storage, quantitative and computational methods for archaeological research, virtual tours for educational purposes and for the preservation of the cultural heritage

Laura Burigana, PhD candidate (s. 2018) in Archaeology at University of Padua (Italy). Working mainly on innovative means of investigation of archaeological artefacts and landscapes, through remote sensing, geographical information systems (GIS) management, digital image processing, and Agent-based Modelling (ABM).

Armando De Guio is Senior Professor in Methods and Techniques of Archaeological Research at the University of Padua. He has developed a domain of expertise spread in a wide range of disciplines: General Method and Theory, Quantitative Archaeology (from Seriation to Survival Analysis, Spatial Analysis, GIS, Expert Systems, Simulation and Modelling, CNN), Surface Archaeology, Remote Sensing, Landscape Archaeology, Demographic Archaeology, Conflict Archaeology, Ethno-Historical Archaeology, Experimental Archaeology, Public Archaeology, and Eco Cultural Resource Management. In his major field of practical activity, Surface Archaeology, Armando De Guio is also president of the CISAS (International Centre for the Study of Surface Archaeology) and is directing several long-term field surveys that have involved far reaching collaborations with major Italian and international institutions.

Marta Sara Cavallini (Museum of Archeology and Ethnology of the São Paulo University (MAE/USP), Brazil)

Claide de Paula Moraes (Program of Anthropology and Archeology Program of the Federal University of Western Pará (PAA-UFOPA), Brazil)

She is a PhD student at the Museum of Archeology and Ethnology of the São Paulo University, (MAE/USP), MSc degree in archeology from the same Institution and graduated in Ancient Literature and Archaeology, Universitá di Bologna (UNIBO), Bologna, Italy (2007) with a specialisation in Archaeology (Prehistory). She has been researching since 2008 in Amazonian pre-colonial archaeology, with a focus on Rock Art investigation. She is a member of the ARQUEOTROP (Archaeology of the Tropics Laboratory) and she is an associate researcher at Museu da Amazônia MUSA, Manaus, Amazonas, Brazil.

He is an archaeologist, professor in the Anthropology and Archaeology Program at the Federal University of Western Pará (UFOPA) and postdoctoral fellow in the Anthropology program at the University of São Paulo. He was coordinator of the Bachelor’s Degree in Archaeology at UFOPA between 2014 and 2016. PhD in Archaeology at the USP Archaeology and Ethnology Museum; master in archeology by the same institution; and graduated in History from the Pontifical Catholic University of Goiás. He specialises in Amazonian archaeology, with a primary interest focused in archeology in dialogue with indigenous

Laura Burigana (Department of Cultural Heritage: Archaeology and History of Art, Cinema and Music, University of Padua, Italy)

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Contributors peoples; initial settlement of the Amazon; formation process of the archaeological record; lithic technology, ceramic technology; socio-political dynamics of the Amazon in the year 1000; experimental archaeology and teaching archaeology.

of Mediterranean and Oriental Cultures of the Polish Academy of Sciences in Warsaw. She is a broadly trained archaeologist of North Africa and the Near East with expertise in the archaeology of the Nile Valley, particularly of Nubia, and the Sahara. She has held research, teaching and curatorial positions at Yale University, University of Leicester, University of Birmingham, the American University in Cairo, and the British Museum. She is the co-Director of the Aswan-Kom Ombo Archaeological Project.

Steve Dickinson (Independent researcher) He is an independent researcher specialising in the archaeology of the Lake District, Cumbria, U.K. He has been conducting excavations and surveys in the Lake District World Heritage Site since 1980,and is a member of the Prehistoric Society. He is currently coordinating a new research programme centred on a newly discovered array of Neolithic sites in SW Cumbria.

Luigi Magnini (Department of History, Human Sciences and Education - University of Sassari, Italy) Luigi Magnini is researcher and lecturer in Methods and Techniques for Archaeological Research at the University of Sassari (Italy). He is specialised in Landscape Archaeology and in the study and interpretation of remotely sensed data (UAV, aircraft, and satellite-based), with particular interest in artificial intelligence, automation, and object-based image analysis applied to archaeological research. Since 2014 field coordinator and now director of the excavation in the Protohistoric village of Bostel di Rotzo (northern Italy). He has actively participated in several national and international projects on the topics of Conflict Archaeology, Digital Archaeology, Preprotohistoric Archaeology, and Ethnoarchaeology.

Miguel Espino Villarreal (Independent researcher and freelance consultant) Experienced Panamanian field archaeologist with a long trajectory in the archaeology of Minas Gerais state, Brazil. He has broad-spectrum experience, but somewhat focused on lithic archaeology. Also encouraged by archaeologists Eduardo Neves and Fernando Costa, to be part of the Central Amazon Project (PAC), he moved on to Amazonas state and became an important asset to several fieldworks. Emanuela Faresin (Department of Cultural Heritage: Archaeology and History of Art, Cinema and Music, University of Padua, Italy)

Carla Mannu (Centro Studi “Identità e Memoria” (CeSim/APS), Italy)

Emanuela Faresin is PhD in Study and Conservation of Archaeological and Architectural Heritage at the Department of Cultural Heritage, University of Padua. She is currently a laboratory technician at the University of Padua as a specialist in 3D surveying and modelling, point cloud processing and data output management (reconstructions in virtual/augmented/mixed reality). She also deals with 3D printing with particular attention to the aspects of valorization and inclusiveness.

Carla Mannu, graduated in Electronic Engineering at the Engineering Faculty of the University of Cagliari, with a thesis on the 3D processing systems of prehistoric rock engravings. For years, she has collaborated with Prof. Tanda in the study of engraved rock art, carved and painted.

Gianni Furiassi (Independent researcher and freelance consultant)

Art Historian and Archaeologist, University of Santiago de Compostela, Spain. Graduate in History of Art with a master’s degree in Archaeology. Currently a PhD student at the University of Santiago de Compostela. Member of the research group Síncrisis. Investigación en Formas Culturais (USC).

Vanesa Mariño Calvo (University of Santiago de Compostela, Spain)

Archaeologist with a master’s degree from the University of “G. d’Annunzio” in Chieti (Italy), since 2014 he has been a freelancer in the Preventive Archaeology field. Previously he collaborated with professional firms in central Italy in restoration and conservation of Cultural Heritage projects and in the Relief and Archaeological Documentation field. He carries out geophysical investigations applied to archaeological research in Italy and abroad, in various archaeological contexts. At present, in addition to the profession, he is an independent researcher and deals with digital documentation of archaeological contexts bearing traces of rock art.

Alberto Marretta (Parco Archeologico Comunale di Seradina-Bedolina, Italy) He is a rock art researcher focused on Valcamonica and other Alpine sites. He works as Scientific Director of the Archaeological Park of Seradina-Bedolina (Capo di Ponte, Valcamonica), has conducted several documentation fieldworks in the Central Alps and has devoted extensive research on various topics concerning rock art. He is author of many scientific papers and monographs and has active collaborations with numerous museums and international institutions.

Maria C. Gatto (Polish Academy of Sciences, Poland) Maria Carmela Gatto is a researcher at the Institute x

Contributors Eloy Martínez Soto (University of Vigo, Spain)

In 2001, he graduated in Geography at the Federal University of Pará (UFPA). Later, he obtained a Master degree in Archaeology from the Federal University of Piauí (UFPI). Currently, he is a PhD student in the postgraduate Program of Anthropology at the Federal University of Pará (UFPA), where he developed research on archaeological sites in natural cavities in the Carajás mountain range. He has experience in the area of Geography and Archeology, acting on the following subjects: amazonian archeology, pottery analysis, Maracá culture funerary urns, and mapping of archaeological sites.

Historian and Archaeologist, University of Vigo, Spain. Graduate in History with a master’s degree in History, Territory and Heritage resources. Currently a high school History teacher. Member of the archaeology section of the Miñoráns Studies´ Institute (IEM). Vice-president of Amigas e Amigos do Museo de Pontevedra Association. Angelo Martinotti (Istituto Archeologico Valtellinese, Italy)

Radosław Palonka (Department of New World Archaeology/Institute of Archaeology, Jagiellonian University in Kraków, Poland)

Archaeologist, he deals with prehistory and protohistory of Northern Italy. He participated in excavations and research in Lomellina (province of Pavia, Italy), Valcamonica and Valtellina, dedicating himself especially to Alpine rock art, a theme that he has developed in numerous local, national and international scientific publications.

Associate Professor at the Department of New World Archeology, Institute of Archaeology of the Jagiellonian University in Krakow (Poland) and Research Associate at the Crow Canyon Archaeological Center, Colorado (USA). He specialises in archaeology and anthropology of North America, particularly the US Southwest. Since 2011 he has been leading the archaeological project focusing on socio-cultural and settlement changes in the thirteenth century A.D. Ancestral Pueblo culture from the central Mesa Verde region, southwestern Colorado within the Canyons of the Ancients National Monument. His research interest also connects with the documentation and analysis of the pre-Hispanic Ancestral Pueblo and historic Ute and Navajo rock art. He cooperates with several American institutions as well as the members of the Hopi tribe from the Hopi Culture Preservation Office (Second Mesa, Arizona) in terms of the indigenous oral traditions and knowledge. He applies various digital techniques in the process of documentation, conservation, and protection of cultural heritage. He is also involved in popularising archaeology and history of Native Americans in Poland and in Europe.

Levemilson Mendonça “Lei’’ da Silva (Independent researcher and freelance consultant) Expert field archaeologist from Iranduba, Amazonas. He is an Amazonian self-made and all-in-one man, native to the things of that land. Encouraged by the archaeologist Eduardo Neves (MAE-USP) to be part of his Central Amazon Project (PAC) team, since the late nineties, he rapidly became a skillful and experimented field archaeologist developing invaluable participation in several fieldworks of many derived research projects. He had a crucial role in the topographic campaign of 2008, as an Arara Vermelha project crew member. Paula Morgado (Municipality of Monforte - Centre for Art History and Artistic Research, Portugal) She has a master in Museology (University of Évora) and a degree in Archaeology (University of Lisbon). She is an archaeologist at the Municipality of Monforte and researcher at CHAIA (Centre for Art History and Artistic Research). Her research, although diverse, is mainly focused in Alentejo. She has extensive experience in directing (or participating in) national research projects. Published papers in peer reviewed journals and has several participations in national and international congresses.

Agustina Papú (Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Instituto Nacional de Antropología y Pensamiento Latinoamericano (INAPL), Argentina) Agustina Papú is a PhD student in Archaeology at the University of Buenos Aires. She has a degree in Anthropological Sciences (with a specialisation in Archaeology) and currently holds a doctoral grant awarded by Argentina’s National Scientific and Technical Research Council (CONICET) to study early rock art in the Argentinian Patagonia.

Alexandre Paz-Camaño (University of Santiago de Compostela, Spain) Archaeologist and independent researcher, University of Santiago de Compostela, Spain. Graduate in History with specialisation in Prehistory and Archaeology. Currently field archaeologist and manager in BETILO, Arqueoloxía e outras Historias for development of archaeological projects and Cultural Heritage dissemination.

Leonor Rocha (School of Social Sciences - University of Évora, Portugal) She has a doctorate in Archaeology, in the Prehistory specialty at the University of Lisbon. She is currently a professor of Archaeology at the University of Évora and a researcher at CEAACP (Centre for Studies in Archaeology, Arts and Heritage Sciences). Her research

Carlos Augusto Palheta Barbosa (Instituto Nacional do Patrimônio Histórico e Artístico Nacional in the State of Pará (IPHAN - PA), Brazil) xi

Contributors on Recent Prehistory is focused in Alentejo Megalithism and Rock Art. She has extensive experience in directing (or participating in) national and international research projects, supervising master’s and doctoral dissertations. In addition to publishing books and articles, she is a member of the editorial committee of journals, and also reviewer for articles within her specialty.

working on projects using Virtual Reconstructions and Virtual Reality Tours of archaeological sites for scientific, educational, and communication purposes.

Giuseppe Salemi (Department of Cultural Heritage: Archaeology and History of Art, Cinema and Music University of Padua, Italy)

He has an undergraduate degree in History (2000), an MSc degree in Prehistory (2003), both from the Federal University of Pernambuco (UFPE), and a PhD in Archaeology at the Archeology and Ethnology Museum (MAE-USP) (2012). Currently, he is an Associate Professor in the Anthropology and Archaeology Program at the Federal University of Western Pará (UFOPA-PAA), where he has been teaching and researching since 2012. His research topics involve rock art, archaeology and ethnography. Raoni has developed intercultural research with various Indigenous peoples in Amazonia since 2005 and in the NE of Brazil since 2001. He also coordinates the Visual Anthropology and Archaeology of Image Laboratory (LAVAI-UFOPA).

Raoni BM Valle (Program of Anthropology and Archeology Program of the Federal University of Western Pará (PAA-UFOPA), Brazil)

Giuseppe Salemi is Associated Professor of Geomatics at the University of Padova. The scientific activity concerns advanced numerical and computational techniques for geodetic, topographic and photogrammetric applications, at small, medium and large scale in the framework of cultural heritage. The main topics are: laser scanning, point cloud processing, digital image processing and computational photography, data mining, spatial databases, and multimedia cartography. Filippo Stampanoni Bassi (Museu da Amazônia – MUSA, Manaus, Amazonas, Brazil)

Jaime Xamen Wai Wai (Federal University of Western Pará (UFOPA), Brazil)

Deputy Scientific Director of the Museu da Amazônia – MUSA. PhD in Archaeology at the USP Archeology and Ethnology Museum (MAE/USP) (2016), and bachelor in Ancient Literature and Archaeology, Universitá di Bologna (UNIBO), Bologna, Italy in 2008 with a specialisation in Archaeology (Prehistory). His research topics involve Amazonian Archaeology, settlement patterns, household archaeology, Rock Art and heritage management with traditional communities.

He became the first Indigenous undergraduate in archeology in Brazil by the Federal University of Western Pará (UFOPA). He is currently in the process of completing his master’s research in The Federal University of Minas Gerais, which aims to tell the ancient stories of the Kikwo River region, an important river in the trajectory of the Wai Wai people. His goal is to tell this story from a Wai Wai perspective and in dialogue with archaeology and the scientific academy. In addition, he is vice president of the Association of Indigenous Peoples of Mapuera (APIM). He was an invaluable field assistant, excavator and surveyor during the 2014 excavation campaign.

Giuseppa Tanda (Cagliari University; President of Centro Studi “Identità e Memoria” (CeSim/APS), Italy) Giuseppa Tanda is a retired professor of Prehistory and Protohistory at the University of Cagliari, director of the “Centro Interdipartimentale per la Preistoria e Protostoria del Mediterraneo” (C.I.P.P.M.) and the School of Specialisation in Archaeological Heritage, until 2012. In 2017, she founded the “Centro Studi Identità e Memoria” (CeSim /Aps), of which she is President. She carried out an intense research and excavation activity in Italy and abroad, from the Neolithic, to the Iron Age, in a Euro-Mediterranean perspective and with an interdisciplinary approach. She has published over 300 works on different topics, including about 90 articles about the art of the domus de janas.

Bolesław Zych (Institute of Archaeology, Jagiellonian University in Kraków, Poland) Archaeologist and faculty member at the Department of New World Archeology, Institute of Archaeology of the Jagiellonian University with extensive experience in archaeological projects conducted in Poland, Guatemala, Germany, and the USA. His research in the field of archaeology focuses on the application and using various digital methods, including photogrammetry, terrestrial laser scanning (TLS), unmanned aerial vehicle (UAV) or Reflectance Transformation Imaging (RTI). His research interests include analysis in the virtual environment: analysing and digitisation of the data and 3D modelling of architectural remains, rock art, and the surrounding landscape using various software as well as the dissemination of new forms of three-dimensional visualisations. Participant in many conferences and workshops in Poland, Italy, Germany, and Great Britain on digital archaeology and application of digital techniques in rock art, settlement research, and GIS/spatial analyses.

Alberto Urcia (Yale University, USA) Specialist in Digital Archaeology and Preservation of Cultural Heritage. For the past decade, Alberto has been managing the data recording and documentation for several international expeditions. Since 2012 he has been employed at Yale University (USA) where his primary focus is on developing innovative methods to support archaeological research in Egypt. He is currently xii

Abstract The monograph entitled Rock Art Research of the Digital Era: Case studies from the 20th International Rock Art Congress IFRAO 2018, Valcamonica (Italy) covers the research presented in several sessions that took place at the 20th International Rock Art Congress (IFRAO) held in Darfo Boario Terme, Valcamonica (Italy), from the 29th of August to the 2nd of September 2018. With a broad understanding of Digital Archaeology, different specialists in this book show how digital technologies can benefit the study of rock art in a variety of themes. Digital methods and 3D modelling are clearly changing the field of rock art documentation and interpretation, with new approaches that allow us to make eroded rock art panels more visible, especially in those cases where the human eye or a raking light is ineffective. Over a range of case studies, this book demonstrates how cutting-edge methodologies are integrated within 3D modelling workflows, and how these can manage and disseminate the results to the general public in an interactive way. DOIs to additional online material can be found at the end of chapters 2 and 6.

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Introduction Miguel Carrero-Pazos, Rebecca Döhl, Julian Jansen van Rensburg, Paolo Medici, Alia Vázquez-Martínez The expansion of computer technology within Archaeo– logical Science has contributed to the growth of a variety of new approaches in archaeological research. Specifically, the representation and analysis of archaeological sites and objects by means of virtual reconstruction. This is particularly noticeable within rock art studies, where 3D modelling has been used in the documentation, evaluation, dissemination, and historical analysis of rock art.

monograph is composed of 11 chapters from these sessions and offers a comprehensive insight into the application of digital technologies within rock art research. I.1 Interdisciplinarity, archaeological data and methods The need to find research tools beyond the traditional, coupled with the technological innovation of the last thirty years has expanded the development of new documentation methods and of archaeological data representation. In historical and archaeological studies this technological innovation is extensively used within an interdisciplinary framework that utilises traditional and new methods. A change that has broadened horizons. Among these new methods a large contribution has been made by computer sciences, both hardware and software, mathematics, optics, physics, mechanics and network communication. Thanks to this innovation, it has been possible to refine the traditional recording methods with these digital methodologies confirming the centrality of their role and taking advantage of the many opportunities offered by the continuous advance of technical and computer-based methods.

This monograph demonstrates, through different case studies, how digital approaches can benefit rock art research by providing new visualisations for rock art panels with different levels of preservation and, by using these, extracting historical and archaeological information. These case studies also demonstrate how cutting-edge methodologies are integrated within 3D modelling workflows and how the results can be managed and disseminated to the general public. The 20th International Rock Art Congress, IFRAO 2018, Standing on the Shoulders of Giants, held in Darfo Boario Terme, Valcamonica, Italy, from the 29th August to the 2nd of September 2018, was one of the largest rock art conventions, with more than 800 people participating, 530 scientific papers presented, and over 36 sessions organised. Among these were three sessions concerned especially with digital technology and its usage within rock art research:

Four studies presented in this monograph highlight the application of this interdisciplinary approach and its results. Rocha and Morgado, in the municipality of Monforte (Portugal), studied the site of Penedo do Ferro, a prehistoric open-air sanctuary. This project showed the integration of photogrammetry techniques in order to help to obtain a better documentation of the engravings. The research team combined the documentation of the area with Georeferencing (GPS) and a photographic survey, to obtain both a photogrammetry and a threedimensional view of each panel. The combined work of these techniques resulted in a good characterization of the rock art present, even where the surface was almost indecipherable. A similar approach has been used also by the team led by Paz-Camaño, who worked on Iron Age engravings in Western Galicia. This work documented the rock art panel by employing digital photography and photogrammetry, that was complemented by a geological analysis of the stone. The results offered important information and produced a wide variety of different imagery products that were used to enhance the visibility of the rock art. The article of Dickinson combines the integration of archaeological assessment with the benefit of digital imaging, including the comparison of the Upper Eskdale site and the engravings from other sites. He focused on the polissoir and the incorporation of digital image interpretation, 1:1 tracing and digital graphical

• Challenges and changes for rock art research in the digital age, a session centred around the possibilities and consequences of digital technologies applied to rock art concerning recording, dissemination and digital curatorship of rock art, and rock art heritage management. • Rupestrian archaeology, question & answers: tools, methods and purpose, which focused on the relationships between methods, techniques of analysis and goals of the archaeological research applied to rock art studies. • Made for being visible. Developing 3D methodologies for the study of rock art carvings. Managing suitability in sites with Rock Art. The purpose of this session was to present different case-studies centred on the application of 3D modelling and post processing techniques in relation to the study of rock art carvings. Four years later, with a world pandemic having stopped our lives for over a year, we can now present the proceedings of these sessions, all of which focus on the application of digital methodologies within rock art research. This 1

Miguel Carrero-Pazos, Rebecca Döhl, Julian Jansen van Rensburg, Paolo Medici, Alia Vázquez-Martínez transcription of specific features. In the fourth study, we look at the Arara Vermelha Rock Shelter, Roraima, Brazil with the team of Cavallini, where the preservation of archaeological layers offered greater chances for rock art contextualization and dating. This project demonstrated how the use of AMS radiocarbon dating can lead to better understanding the graphic transformations and in the defining of a chrono-stylistic analysis of the rock art.

of archaeological carved remains, such as rock art, inscriptions, or emblems. In the last decades, there has been a wide expansion on the use and application of techniques such as SfM Photogrammetry and laser scanning (Robin 2015). Reflective Transformation Imaging is also being adopted in cultural heritage to highlight the readability of incised surfaces, such as rock art, wall graffiti (Valente 2020).

I.2 3D modelling, Photogrammetry, RTI

Following these developments, the use of digital image techniques to improve the visualisation of the engraved panels has become a particular field of research (see e.g., Mudge et al. 2006, 2012; Díaz-Guardamino, Wheatley 2013; Olsen, Bryant 2013; Duffy 2013; Domingo et al. 2013; Pires et al. 2014). In technical terms, these approaches use several filters and analyses over the created 3D models to highlight their morphological features, evolving to digital tracings of the rock art panels that try to surpass the traditional hand-drawn based techniques. One of the most used is Radiance Scaling (Vergne et al. 2010; Granier et al. 2012). Currently widespread through the MeshLab open-source software, its fast application allows the highlighting of the different views of a 3D model. Thus, it allows a more detailed view over rock art panels (Vázquez-Martínez et al. 2016). The list of techniques includes the management of mesh comparisons and manipulating shadows over the 3D models at different scales (e.g., exaggerated shading, Carrero-Pazos et al. 2018), and the application of traditional raster and LiDAR visualisation techniques (Lymer 2015; Horn 2019).

The documentation of rock art is one of the most important factors for a good interpretation of these manifestations. For years, researchers have used manual methods for the reproduction of rock art, which have a great impact on the panel in the moment of its documentation, for example, tracing on plastic sheets or the rubbing technique. Both methods have a negative impact on the conservation of the panel, yet are still being used frequently. From the 21st century, there has been a major change in the methodology of the documentation of the rock art, and the manual documentation techniques had been replaced by digital techniques. Digital techniques allow 3D virtualisation of the engravings as well as a detailed and reliable study of rock art. The current digital methodology is the result of an improvement of digital techniques that were first experimented at Stonehenge in the late 1960s (Atkinson 1968). The digital representation of rock art has also become a tool for dissemination. The acquisition of the data necessary for the creation of 3D models requires a good choice of methodology that depends on the variables that affect the documentation phase. The main methods of data acquisition today, which we will see in the articles of this book, are: Laser Scanning, Structure from Motion (SfM) photogrammetry and Reflectance Transformation Imaging (RTI). The main difference between them is the handling of the instruments according to the accessibility of the site and the derivation of the 3D point cloud. Laser Scanners provide range data that contains the 3D coordinates needed for the mesh generation phase, i.e., they extract the points from reality by themselves. Whereas Photogrammetry and RTI obtain data taken from 2D images that require further processing to transform them into 3D information.

The present monograph highlights the application of digital filters to improve the visualisation of the 3D rock art models. Tanda and Manu take this opportunity to present new research over the famous Domus de Janas, by applying DStretch analytical imaging filters, thereby providing new insights into the paintings within the funeral hypogea. Bettineschi et al. present the results of the application of LiDAR-derived enhancing techniques over several engravings from the vertical walls of the Assa Valley, in Vicenza. The application of multiple digital methods allows them to discuss the motifs and techniques used. Finally, Papú demonstrates how digital techniques can be used to unravel long-term complex sequences of superimpositions at the Cerro de los Indios 1, in Santa Cruz (Argentina). I.4 Display and interaction with data

The use of these techniques in rock art and the results obtained from them are explained in several of the articles in this book. Palonka and Zych show the benefits and disadvantages of these three techniques, highlighting not only the results obtained but also the ease and difficulty of each. Furiassi focuses on the use of the laser scanner and Martinotti and Marretta on the reproduction of a panel utilising SfM photogrammetry.

A new way of presenting and looking at the output of 3D digitization processes has come into focus: “virtuality”. A term that encompasses 3D computer graphics, Augmented Reality (AR) and Virtual Reality (VR)1.   The two terms are not always clearly distinguished from one another. Virtual Reality creates a completely virtual 3D world for the observer, in which the observer can “move” and interact with it. This is usually done with the help of VR equipment, such as glasses, gloves, etc. In Augmented Reality, the observer perceives the real world, but additional, virtual information is added to it, using simple devices such as e.g., a smartphone. 1

I.3 Digital analysis and enhancing techniques 3D modelling and Digital Imaging Techniques are currently a standard in data acquisition and analysis 2

Introduction Virtual environments have the advantage of being able to combine spatial information with contextual annotations and give the observer an interactive three-dimensional insight into the real-world appearance of the object and its environment.

An increasingly popular form of using virtual simulated environments are virtual tours. One of the first virtual tours started in 1994 with the virtualization of Dudley Castle4 with a “walk-through” of a 3D reconstructed castle dated to 1550. From this starting point, virtual tours have evolved to modern game-based tours5, which can convey scientific content to an audience. Urcia et al. (this volume) presents the setup of an interactive virtual reality tour of the rock art area in Nag el Hamdulab, Aswan, Egypt. They stress the necessity of not only recording the site in 3D, but also in reconstructing the perception between the viewer, the image and the landscape in which it is embedded. The advantages proposed by Urcia et al. are that virtual reality can bring specialist knowledge to an audience and be used as an innovative tool for research purposes.

The use of virtual environments was first undertaken in the 1970s within the fields of engineering, aviation and the military, before it entered the realm of gaming and entertainment in the 1980s and 1990s. By the 1990s, this application also found its way into museums and cultural heritage institutions, where it was used to create a new medium for interacting with objects and the transfer of knowledge. At the end of the 1990s it began to be more widely used in archaeology,2 where it has been used in knowledge transfer, making inaccessible sites virtually accessible, and to allow for the interactive appropriation of a reconstructed past with associated scientific questions. Moreover, it has been proposed to undertake virtual exca­ vations as a learning aid (Reilly 1990). Unsurprisingly, the use of VR has also found its way into rock art research.3

The editors, on January 2021 References Atkinson, K. B. “The recording of some prehistoric carvings at Stonehenge”. The Photogrammetric Record, 6 (31) (1968): 24–31.

However, the term “virtual” includes various degrees of integration of the senses, interactivity and detachment from the real world. While in the early applications the very existence of virtual solid models or 3D models has been understood as virtual (Reilly 1990: 1), Barceló et al. (2000: 1) state that “virtuality” must at least include a sensory experience. The technical basis for virtual environments, both in the acquisition of the data and in the presentation of it, has changed significantly since the first use of virtual environments. The limitations of the presentation of the data were first defined by computing capacity and the development of devices necessary for a full 3D experience. However, with the development of ever faster computers and virtual reality devices, such as headsets, it is now possible to have a higher degree of rendering and interactivity that allows annotations with information in addition to the “simple” 3D experience. Moreover, unlike the 1990s, we are now able to complete reconstruction of archaeological excavations utilising laser scanners and Structure from Motion (SfM) Photogrammetry.

Carrero-Pazos, M., Vilas-Estévez, B. and VázquezMartínez, A. Digital imaging techniques for recording and analysing prehistoric rock art panels in Galicia (NW Iberia). Digital Applications in Archaeology and Cultural Heritage 8 (2018): 35-45. https://doi. org/10.1016/j.daach.2017.11.003 Barceló, J. A., M. Forte and D. H. Sanders (ed.), Virtual Reality in Archaeology: Computer Applications and Quantitative Methods in Archaeology BAR Publishing, Band 843). Oxford: BAR Publishing. 2000. Díaz-Guardamino M. and Wheatley D. ``Rock Art and Digital Technologies: the Application of Reflectance Transformation Imaging (RTI) and 3D Laser Scanning to the Study of Late Bronze Age Iberian Stelae”. MENGA. Revista de Prehistoria de Andalucia 4 (2013): 187-203. Domingo, I., Villaverde, V., López-Montalvo, E., Lerma, J. L. and Cabrelles, M. “Latest developments in rock art recording: towards an integral documentation of Levantine rock art sites combining 2D and 3D recording techniques”. Journal of Archaeological Science 40 (2013): 1879-1889.

  For the implementation of virtuality in archaeology in the 1990s, see: Reilly, P. ‘Towards a virtual archaeology.” Computer Applications in Archaeology. Oxford: British Archaeological reports (Int. Series 565), 1990 and Gillings, M. “Engaging Place: A Framework for the Integration and Realisation of Virtual-Reality Approaches in Archaeology.” In Archaeology in the age of the Internet. CAA 1997. Edited by L. Dingwall, S. Exon, V. Gaffney, S. Laflin, M. Van Leusen. Oxford: British Archaeological Reports (Int. Series, S750), 1999. For virtual projects in the 2000s, including archaeology, see: https://3dvisa.cch.kcl.ac.uk/index. html (Last accessed: 23.11.2021). For a summary of the state of research of VR in archaeology in the 2000s, see: Barceló, J. A., M. Forte and D. H. Sanders (ed.), Virtual Reality in Archaeology: Computer Applications and Quantitative Methods in Archaeology (BAR Publishing, Band 843). Oxford: BAR Publishing. 2000. 3   There exists a range of projects, which apply virtuality as a means to explore rock art, e.g., 3D-Pitoti project: http://3d-pitoti.eu/index.php/ project-details (Last accessed: 23.11.2021). British Museum rock art project: https://africanrockart.britishmuseum.org/vr/ (Last accessed: 23.11.2021) Virtual Museum Canada: https://images danslapierre.mcq. org/en/ (Last accessed: 23.11.2021). 2

Duffy, S. M. Multi-Light Imaging for Heritage Applications. English Heritage Swindon, 2013. Gillings, M. “Engaging Place: A Framework for the Integration and Realisation of Virtual-Reality Approaches in Archaeology.” In Archaeology in the age of the Internet. CAA 1997. Edited by L. Dingwall, S. Exon, V. Gaffney, S. Laflin and M. Van Leusen. Oxford: British Archaeological Reports (Int. Series, S750), 1999.   http://www.exrenda.com/dudley/index.htm  (Last accessed: 23.11.2021).   E.g.: Ubisoft Discovery Tours, https://www.ubisoft.com/de-de/game/ assassins-creed/discovery-tour  (Last accessed: 23.11.2021) 4 5

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Miguel Carrero-Pazos, Rebecca Döhl, Julian Jansen van Rensburg, Paolo Medici, Alia Vázquez-Martínez Granier, X., Vergne, R., Pacanowsky, R., Barla, P. and Reuter, P. “Enhancing Surface features with the radiance scaling MeshLab plugin”. In Archaeology in the Digital Era, Volume II, edited by E. Graeme, T. Sly, A. Chrysanthi, P. Murrieta-flores, C. Papadopoulos, I. Romanowska and D. Wheatley, 417-422. Amsterdam: Amsterdam University Press, 2012

Vergne, R., Pacanowski, R., Barla, P., Granier, X. and Shlick, C. “Radiance Scaling for Versatile Surface Enhancement”. In I3D ‘10 Proceedings of the 2010 ACM SIGGRAPH symposium on Interactive 3D Graphics and Games. ACM 143-150, 2010

Horn, C., Pitman, D. and Potter, R. “An evaluation of the visualisation and interpretive potential of applying GIS data processing techniques to 3D rock art data”. Journal of Archaeological Science: Reports 27 (2019), 101971. https://doi.org/10.1016/j.jasrep.2019.101971 Lymer, K. “Image processing and visualisation of rock art laser scans from Loup’s Hill, County Durham”. Digital Applications in Archaeology and Cultural Heritage 2 (2015): 155-165. Mudge M., Malzbender T., Schroer C. and Lum M. (2006). “New Reflection Transformation Imaging Methods for Rock Art and Multiple-Viewpoint Display”. In The 7th International Symposium on Virtual Reality, Archaeology and Cultural Heritage VAST (2006), edited by M. Ioannides, D. Arnold, F. Niccolucci and K. Mania, 195-202. Mudge, M., Schroer, C., Noble, T., Matthews, N., Rusinkiewicz, S. and Toler-Franklin, C. “Robust and Scientifically Reliable Rock Art Documentation from Digital Photographs”. In A Companion to Rock Art, edited by J. Mcdonald and P. Veth. Blackwell Publishing, Malden, USA, 2012. Olsen S.L. and Bryant T. ``Stories in the Rock: Exploring Saudi Arabian Rock Art”. Carnegie Museum of Natural History Pittsburgh (2013). [see also http://saudiarchaeology.com/, consulted 16/01/2017]. Pires, H., Fonte, J., Gonçalves-Seco, L., Correia Santos, M. J. and Sousa, O. “Morphological Residual Model. A Tool for Enhancing Epigraphic Readings of Highly Erosioned Surfaces”. In EAGLE- Information Technologies for Epigraphy and Cultural Heritage in the Ancient World, 133-144. Paris, 2014. Reilly, P. “Towards a virtual archaeology.” Computer Applications in Archaeology. Oxford: British Archaeological reports (Int. Series 565), 1990. Robin, G. “Editorial”. Digital Applications in Archaeology and Cultural Heritage 2 (2015): 35-40. Valente, R. and Barazzetti, L. “Methods for ancient wall graffiti documentation: Overview and applications”. Journal of Archaeological Science: Reports 34, (2020) 102616. doi: 10:1016/j:jasrep:2020:102616. Vázquez Martínez, A., Carrero Pazos, M. and Vilas Estévez, B. “Campo Lameiro 3.0. Nuevas metodologías de registro para el arte rupestre de Galicia (España)”. BCSP Bollettino del Centro Camuno di Studi Preistorici 42 (2016): 29-40. 4

Introduction

Case studies in this book

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1 The Arara Vermelha Rock Shelter, Roraima, Brazil: perspectives Concerning Amazonian Sheltered Petroglyphs Marta Sara Cavallini, Raoni BM Valle, Filippo Stampanoni Bassi, Claide de Paula Moraes, Márcio Amaral, Carlos Augusto Palheta Barbosa, Marcos Eugênio Brito de Castro, Rogério Andrade, Manoel Fabiano da Silva Santos, Jaime Xamen Wai Wai, Levemilson Mendonça “Lei’’ da Silva, Miguel Espino Villarreal † Abstract Among the known petroglyph sites in the Brazilian Amazon, very few are located in rock shelters, where the preservation of archaeological layers offers greater chances for rock art contextualization and dating. Since 2008, one such case has been investigated, the Arara Vermelha site, in the Roraima State. Though still in its incipient stage, our research has produced radiocarbon dates for the human occupation of the shelter beginning from the Early Holocene. This chapter focuses on these preliminary results and their implications for future investigations regarding petroglyph dating and contextual understanding amidst Amazonian rock art. Keywords Amazonian rock art – Sheltered petroglyphs – Archaeological context – Rock art dating – Amazonian archaeology 1.1 Introduction

the objective of reaching a contextual archaeological comprehension. Indeed, most known Amazonian rock art sites are in open-air and riverine locations, and, due to pronounced seasonal flooding, they remain underwater for most of the year. That circumstance has restricted the potential for indirect dating by stratigraphic association with archaeological layers, while also preventing assessments of the material contexts of rock art production. Additionally, hydraulic erosion and heavy tropical weathering of rock surfaces have challenged developing technological and taphonomic analyses of petroglyphs. Moreover, on softer sedimentary rocks, these environmental conditions tend to easily distort internal chronological sequences, increasingly compromising the survival of the most ancient rock art. Upland sheltered sites may provide more secure layers of sediments containing a wealth of chronostratigraphic archaeological data directly associated with petroglyph production and use; however, they are among the least investigated contexts in Amazonian archaeology. Indeed, the minute fraction of studied sheltered petroglyph sites is most certainly a result of sampling bias and limited knowledge of the terrain. Even rarer are those where archaeological surveying, mapping, and excavation have taken place. Known sites include: Werehpai in the Trio Indigenous Territory, Suriname (Stichting Surinaams Museum and Conservation International 2007), Tïhtakariwaïn in the Parque do Tumucumaque Indigenous Land, in Amapá, Brazil (Frikel 1963; Calado 2014), Arara Vermelha, in Southern Roraima, Brazil (Valle 2012, 2017); Miriãporã’wi, in the Middle Tiquié River, Upper Rio Negro Indigenous Land, Amazonas, Brazil (Tenório Tuyuka et al. 2022); and Abrigo do Sol, in Mato Grosso, Brazil (Miller 1987).

A few decades ago, rock art was regarded as poorly informative when brought into the perspective of the broader Amazonian archaeological record. Often overlooked, rock art’s role in the understanding of regional dynamics of human occupation was minimal. This marginality was inherent to the challenge of building a chronological framework for this phenomenon. In most cases, rock art research was characterised by a non-systematic approach in which data-gathering occurred predominantly without

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Marta Sara Cavallini, et al. The first four sites are at the same geological formation, igneous rocks from the Guyana Crystalline Shield, situated in the north and northwest from the main Amazonian rivers. They also have heavily weathered petroglyphs in sheltered contexts. The research team has been intermittently working in the Arara Vermelha (Red Macaw) rock shelter in the Roraima State since 2008. Preliminary results indicate early and middle Holocene occupations in the site’s deposits. Yet, it remains unclear how the radiocarbon dates from charcoal samples recovered from the layers B and C identified inside the shelter relate to the rock art panels just above them.

in South America. Rock art, seen as an archaeological variable, was slowly organised into cultural units inside sequences of social transformations over time. The perspective for a coherent integration, or correlation, of South American and Amazonian rock art into long-term indigenous histories, was, thus, becoming a more feasible possibility (Dubelaar 1986; Williams 1985). However, Amazonian rock art studies in Brazil were not following the same pace. During the 70s, rock art datagathering was still negligible in the Brazilian Amazon (Simões 1983; Simões and Araújo-Costa 1978). As such, rock art was not mentioned in the first regional reconstruction of the human occupation process. The following decade sees no significant improvement. However, in the early 90s, stylistic differences and possible relationships with other Amazonian regions were proposed (Miller 1992a; 1992b; Miranda 1994; Miranda and Souza, 1992; Ribeiro et al. 1986; 1987; 1989; 1996). Those efforts gave room for, a few years later, the first attempt to systematically organise Amazonian rock art into a more wide-ranging regional archaeological scale (Pereira 1996; 2003). Over the 90s, increased attention to meticulous documentation and stylistic analysis became prominent in Amazonian rock art studies. Comparative approaches through analogy with other aspects of the material culture and with ethnography also regained some interest. These approaches sought to explain possible socio-ritual functions of the different sites and their cultural contexts of use and reuse. The analogy with other iconographic expressions, such as ceramic decoration, allowed for inferring cultural relationships between rock art authors and ceramic horizons from dated periods. That resumption of a comparative and contextual approach, articulating rock art and ceramics, aimed at clarifying broader relational perspective of Amazonian iconographies with chronological implications (e.g., Pereira 2010). Rock art research in the Venezuelan Amazon pioneered an integrative approach. That implies the coalescence of rock art analysis into a broader contextual interdisciplinary study. This approach articulates data from several sources: archaeology, linguistic, ethnography, ethnohistory, and paleoecology, seeking to understand rock art’s role in the cultural construction of space (Greer 1995; 2001; Rivas 1993; Tarble and Scaramelli 1999; 2010; Zucchi 2010). In the last three decades, Amazonian rock art investigation has improved rapidly as more researchers became involved. However, the knowledge on its technical, thematic, and stylistic distribution and variability remains poorly understood, let alone framed in time (e.g., Cavallini 2014; Greer 1995; 2001; Pereira 1996; 2003; Riris 2017; Ruiz Estrada 2008; 2010; Tarble and Scaramelli 2012; Ugalde 2012; 2016; Urbina 1991; 2016; Valle 2010; 2012; 2015). Among these recent investigations, two approaches stand out: 1) application of new methods for documentation and analysis (e.g., Castaño-Uribe and Van der Hammen 2005; Kipnis et al. 2013; Pereira et al. 2009; Pereira et al. 2013; Riris and Oliver 2019); 2) efforts for archaeological contextualization (e.g., Cavallini et al. 2015; Ruiz Estrada 2010; Morcote-Ríos et al. 2020; Pereira 2010; Pereira

In this chapter, we firstly present a brief overview of the archaeological background of the Amazonian rock art research. We then report on the results of the first excavation campaign in the Arara Vermelha site (2014). Finally, we make some preliminary considerations about the potential of this site specifically, and of that type of context in general, for tackling the problems of the chronological framework and cultural contextualization of Amazonian rock art. 1.2 Brief Archaeological Background The beginning of the 20th century witnessed the first dedicated rock art expeditions in the Amazon. By then, the first interpretations of its representational character appeared (Coudreau 1901; Koch-Grünberg 1979 [1907]; Ramos 1930-39; Stradelli 1900; 1901; for a little earlier source see, e.g., Wallace 1979 [1853]). These analyses often reflected hyper-diffusionist theories of racist background, which was the intellectual fashion in Europe, attributing a Euro-Asian origin to South American rock art (Brandão 1937; Ramos 1930-39; Thoron 1889). Although, in many cases, information on rock art was sporadic (Albuquerque 1922, 52-71; Katzer 1933, 103-209; Oliveira 1928a; 1928b,14-30; Snethlage 1937, 90-95), eventually, few works came up with entirely dedicated attention to petroglyphs and pictographs (Borges 1933; Rauschert 1959; Vellard 1931). Exploratory journeys for geological, zoological, and ethnological purposes added further information on Amazonian rock art (e.g., Ehrenreich 1948, 91; Frikel 1963; Nimuendajú 1950). Over the second half of the 20th century, contextual and interpretive approaches became more frequent. These tendencies can be exemplified by iconographic analogies comparing Amazonian paintings and petroglyphs with ceramic decoration (e.g., Brajnikov 1974) and by more systematic interpretation of rock art through ethnographic analogies with Native Amazonian cosmological and symbolic systems (e.g., Reichel-Dolmatoff 1967), a trend first envisioned by Stradelli’s pioneering work (Stradelli 1900). From the 70s onward, especially in the Colombian and Venezuelan Amazon and its vicinities, it was possible to see methodological improvements in rock art survey, documentation, and analysis (e.g., Dubelaar 1974; Volsky 1975). By the 1980s, systematic archaeological approaches to rock art became more commonly applied 8

The Arara Vermelha Rock Shelter, Roraima, Brazil and Moraes 2019; Riris 2017; Roosevelt et al. 1996; Scaramelli and Scaramelli 2017; Valle 2017). However, known contexts suitable for testing the association of rock art production, using, and reusing against chronostratigraphic archaeological data is rare in the Amazon, being restricted to scarce occasions.

Amazon, in the south-eastern sector of Roraima State, in the São Luiz do Anauá municipality (00° 51’ 13.4” N, 60° 07’ 55.4 W) (Figure 1.1). The site lies almost on top of a slight rocky elevation, within an island of upland dense forest that rises above recently deforested pastures (Figure 1.2).

1.3 The Arara Vermelha Rock Shelter

The rock shelter formation process began with the tropical weathering exposing parts of the bedrock, forming outcrops. As erosion continues, outcrops partially disintegrate, forming boulders and smaller particles.

Arara Vermelha (also known and recorded as Pedra do Sol) is a granitic rock shelter located on northern Brazilian

Figure 1.1: Localization map of Arara Vermelha site (author: Stampanoni F. B.)

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Marta Sara Cavallini, et al.

Figure 1.2: Topographic map of Arara Vermelha site (author: Stampanoni F. B.) and aerial drone image (author: Cláudio Caetano da Silva).

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The Arara Vermelha Rock Shelter, Roraima, Brazil Boulders are less transportable, tending to remain closer to the outcrop, sliding or falling over other rocks. Eventually, they may rest at sheltered dispositions enabling sediment accumulation. The dimly lit internal space of the shelter comprises 16 square metres, 4.5 metres long and 3.5 metres wide. It is partially obstructed on its east/southeast end, and open on its northwest extremity (Figure 1.3). Its north/ northeast wall contains a heavily weathered palimpsestic panel of mostly geometric petroglyphs (Figure 1.4). A boulder with smoothly weathered geometric petroglyphs blocks the east/southeast side, while few other motifs occur throughout the shelter. That recent deforestation allowed for archaeological surveys surrounding the site. During 2014 fieldwork focused on an area to the southeast of the shelter, resulting in the discovery of 37 rocks with petroglyphs. Later surveys increased those numbers, reaching a total of 91 engraved rocks in an area of 31 hectares. Consequently, this isolated monument became part of a larger rock art landscape.

The identification of the archaeological deposit, indicated by small ceramic fragments, occurred at a depth of 15 cm. At the base of the first layer (A) (Figure 1.5a), between 15 and 20 cm, charcoal samples were recovered in association with other archaeological materials. One of these samples was AMS radiocarbon dated from 1305 to 1190 years BP (Beta 400858/RRPS-PN058 [see images table for mentioned dates]). In the transition between layers A and B, next to the east-southeast petroglyph boulder, the top of a stone structure became evident. During the removal of the topmost clasts, surrounded by layer B sediments, researchers found more charcoal trapped among the cobbles. One of these samples yielded an AMS radiocarbon dated interval from 4290 to 4090 years BP (Beta 400859/ RRPS-PN129). The vertical positioning of some rock slabs inside the structure, found repeatedly during its exposure, suggests anthropic agency rearranging it (Figure 1.5b). In addition, the structured igneous clasts, while not from an exogenous rock type, had different mineral structure, granulometry, and cortex morphology from those of the shelter walls and internal boulders. Another evidence comes from the fine-grained sedimentation of the layers. It indicates a low-energy depositional environment without competence to transport cobble clasts. Together these observations suggest external provenience and human transportation to the shelter interior. An exogenous silicate hammerstone with percussion stigmas found within layer C resting on the structure`s top flat surface (see figure 1.5b and 1.5c) completes the whole scenario. Furthermore, quartz chips, possibly produced by direct percussion, were found nearby. The ongoing analysis seeks a detailed examination of the lithic tool and the debris to clarify their relation with petroglyph production.

Archaeologically known since 2005, research started with opportunistic recordings and preliminary rock art analysis. Accordingly, the initial hypothesis assumed a long historical sequence of petroglyph making, backed up by striking internal variations on taphonomic, technological, and morph-thematic parameters. Therefore, while comprising noticeable techno-stylistic change through time, this palimpsestic deep history of superimposed and juxtaposed layers of thoughts and actions shows the persistence of this small sheltered space for reiterated and different rock art practices over millennia. Moreover, considering the shelter geomorphology, the hardness of the granite, and the heavy weathering state observed in the main panel, a Late Pleistocene origin appears to be plausible (Santos Junior et al. 2018). The planning for more intensive research only became viable after the topographic mapping in 2008 (Valle 2012). Since then, two excavation-dedicated seasons have occurred, 2014 and 2019. The first season was part of a research project funded by the Brazilian National Research Council (CNPQ) and coordinated by Prof. Raoni Valle from Federal University of Western Para (Valle 2017). The second season was coordinated by the first author of this chapter, as part of her Ph.D. project at the Museum of Archaeology and Ethnology of São Paulo University (MAE-USP) and is currently under analysis.

Dismantling the structure’s upper part revealed, in its lower section (layer C), small sealed spaces among the stone fragments that were interposed by minute sedimentary accumulations. Inside one of these lower sealed pockets a third charcoal concentration was collected and dated by AMS radiocarbon from 9485 to 9410 years BP (Beta 400861/RRPS-PN154). That sample consists of the oldest combustion event-related data retrieved from the 2014 excavation, associated with the hypothetically anthropic stone structure. While not constituting a formal in situ hearth structure, the context suggests that anthropogenic fire took place inside the shelter more than 9000 years ago. These results indicate that the Arara Vermelha rock shelter was possibly occupied since the Early Holocene, and provide an account of 8000 years of Indigenous history.

The excavation of a stratigraphic section inside the shelter (N 95 E101, figure 1.5) followed the sequence of natural strata deposited up to the depth of 57 cm. The three strata sequence thus identified was not the end of the archaeological deposit, just the furthest attained during that fieldwork season. However, rigorous control of archaeological remains, granulometry, colour, and compaction of sediments, provided secure interpretation and precise sampling. A stratigraphically consistent sequence of radiocarbon dates, spanning eight thousand years, was thus obtained. Collectively, that evidence enables the inference that slow-paced sedimentation took place in the shelter, with strong indications that there were no long periods without human presence.

Outside the shelter, a second test unit (N 100, 101 E 100, figure 1.6), controlled by artificial levels, revealed an 80 cm-depth deposit with two archaeological layers (A and B) without reaching the bedrock. Two charcoal concentrations in the south-eastern sector of the external test pit were found, one between 50 and 80 cm and another between 60 and 80 cm of depth. These were 11

Marta Sara Cavallini, et al.

Figure 1.3: Arara Vermelha rock shelter site, plan and sections (authors: Castro M. B. and Stampanoni F. B.).

spatially associated with an accumulation of burnt granite laying on the foot of a boulder partially exposed near the shelter entrance. Here, the contextual signature for an insitu fireplace was less elusive and burnt sediments enclosed by the cobbles seemingly conformed to a second lithic arrangement that could be interpreted as a hearth. Four charcoal samples were AMS radiocarbon dated between

1180- and 730-years BP (Beta 400863/RRPS-PN1084; Beta 400860/RRPS-PN1110). During the 2019 excavation season, both test pits were connected by a continuous trench (Figure 1.7). In the process, a fourth deeper and older archaeological layer was found. While its samples and materials have not yet been 12

The Arara Vermelha Rock Shelter, Roraima, Brazil

Figure 1.4: Petroglyphs of the N-NE wall (author: Valle R. B. M.).

analysed, it is likely that this deposit is from a transitional period between the Pleistocene and Holocene.

petroglyphs were already in practice by the onset of the Holocene and may have an earlier origin.

The preliminary results of this research refer to an archaeological sequence spanning from 9000 to 1000 years BP, deposited in close spatial association with a long history of rock art making, using, and reusing. This scenario affords the hypothesis that Guyana Shield

1.4 Discussions The earliest dates associated with rock art contexts (mostly pictographs) so far studied in the Amazon and its closest surroundings situates its production already in the 13

Marta Sara Cavallini, et al.

Figure 1.5: Unit N95 E101 stratigraphic section North (author: Stampanoni, F.B.) and (b) photo of the structure found in 2014 between layers B and C with silicate hammerstone with percussion stigmas found on the structure’s top flat surface (author: Cavallini M. S.).

14

The Arara Vermelha Rock Shelter, Roraima, Brazil Table 1.1: AMS dates. Reference

Date

Test Unit

Layer

Material

Beta 400861/RRPS-PN154

9485 to 9410 Cal years BP

N95/El0l

C

Wood charcoal

Beta 400859/RRPS-PN129

4290 to 4090 Cal years BP

N95/El0l

B

Wood charcoal

Beta 400858/RRPS-PN058

1305 to 1190 Cal years BP

N95/El0l

A

Wood charcoal

Beta 400864/RRPS-PNl114

935 to 800 Cal years BP

Nl00, Nl0l/El00

A

Wood charcoal

Beta 400860/RRPS-PNl110

805 to 730 Cal years BP

Nl00, Nl0l/El00

A

Wood charcoal

Beta 400863/RRPS-PN1084

1180 to 1050 Cal years BP

Nl00, Nl0l/El00

B

Wood charcoal

Beta 400862/ RRPS-PNl118

1065 to 955 Cal years BP

Nl00, Nl0l/El00

B

Wood charcoal

Neves et al. 2012). In the Amazon, only two petroglyph sites on sandstone were studied for chronometric and contextual purposes, Abrigo do Sol (Miller 1983; 1987) and Caretas (Cavallini 2014).

Pleistocene-Holocene transition (Castaño-Uribe and Van der Hammen 2005; Magalhães et al. 2019; Morcote-Ríos et al. 2020; Pereira and Moraes 2019; Roosevelt et al. 1996; Shock and Moraes 2019). Collectively, they indicate three things: 1) the Amazonian biome was extensively occupied by humans during the final Pleistocene; 2) a widespread practice of rock art among those populations; 3) Its early expressions in South America pre-date the mentioned transition, and must be placed into the upper Pleistocene, as complexly developed and widely practised as they were around 12000 years ago (e. g., Bueno and Dias 2015; Correal and Van der Hammen 2001; Dillehay et al. 2015; Guidon and Delibrias 1986; Neves et al. 2012; Parenti 2001; Prates et al. 2020; Vialou et al. 2017).

To enhance our understanding of the dating and contextualization of ancient Amazonian rock art, we focused on petroglyphs located at the Guyana Shield, northern Amazonia. Geological factors such as sheltered geomorphology and resistant igneous lithology guided that sampling. A severe weathering state added taphonomy to the sample choice. Indeed, applying taphonomic logic (Ifrao 2010: 16; Bednarik, 1994), upland sheltered petroglyphs on hard granite lithology, not affected by seasonal flooding and fluvial hydraulic erosion, are perhaps one of the most durable archaeological variables available in humid tropical environments, besides lithic tools. Such contexts may afford access to the most ancient periods of human occupation in Amazonia. Sheltered igneous petroglyphs could have survived from the Late Pleistocene to the present, roughly crossing the 12000 years boundary, much more if buried into sediments (e.g., Bednarik 2001). Depending on the rock matrix and surrounding environment, petroglyphs are generally far more durable than paintings for mechano-mineralogical reasons. If one allows 12000 years for the survival of pictographs in the Amazon, one must also be prepared to assume much older petroglyphs. Therefore, sheltered igneous petroglyphs should be hypothesised as recoverable indexes from the first humans in Amazonia. We think that Arara Vermelha is a suitable candidate for the testing of that hypothesis.

Painted shelters have already proven to be particularly suited to clarify aspects of rock art dating and archaeological context in the Amazon and elsewhere (Guidon and Delibrias 1986; Lage 1999; Morcote-Ríos et al. 2020; Pereira and Moraes 2019; Roosevelt et al.1996). Investigations at Pedra Pintada cave, on the lower Amazon, have shed some light on these issues (Roosevelt et al. 1996; Pereira and Moraes 2019). More recently, compelling data also came from painted rock shelters on the Serranía La Lindosa complex, Northern Colombian Amazon (Morcote-Ríos et al. 2020). These cases have provided evidence showing that pictogram production in the Amazon may well have a Late Pleistocene origin, continuing into the Holocene. Other sporadic evidence has led to Holocene rock art contexts throughout the Amazon. As noticed, these are most upland painted sites, executed on shelters, caves, and outcrops. As in the case of the Pedra Pintada cave, their indirect ages were obtained through the dating of archaeological layers with the fortuitous presence of ochre or pigment samples, pigment drops on lithic tools, paint stains on clasts and boulders, and fallen fragments of the shelter wall with rock art (Castaño-Uribe and Van der Hammen 2005; Correal et al. 1990; Ribeiro et al. 1989; Scaramelli and Scaramelli 2017).

Previous investigations occurred in two similar petroglyph sites: Tïhtakariwaïn (Frikel 1963) and Werehpai (Stichting Surinaams Museum 2007). Protasio Frikel’s pioneering research in the 1950s excavated the Wayana Indigenous people’s sacred place of Tïhtakariwaïn, bringing the problem into perspective, however, without dates. More recently, in southern Suriname, a team from the Stichting Surinaams Museum researched a Trio Indigenous people’s sacred place called Werehpai, a complex of rock shelters. A test pit at one of the shelters provided a sample of charcoal radiocarbon dated in 5000 years BP.

Conversely, only a few petroglyphs rock shelters have been excavated in Brazil so far (Prous 1999; Pessis 2002; 15

Marta Sara Cavallini, et al.

Figure 1.6: Unit N100, 101 E100 stratigraphic sections West, North and East (author: Stampanoni, F.B.).

Protásio Frikel briefly reported his excavation of the sheltered petroglyph site of Tïhtakariwaïn. He identified: a profusion of petroglyphs, scarcity of formal artefacts, even fragments, and the occurrence of fireplaces at the shelter`s entrance. His description seems to echo those of the Suriname team and, in some respects, ours at the Arara

Vermelha. However, Frikel’s account is poorly informed, not to mention that very likely, he ignored important information available in that archaeological context, for example, the charcoal content of the hearth deposit. Frikel, nonetheless, inspired our work in the Arara Vermelha rock shelter, for he has foreseen the potential of these sites. 16

The Arara Vermelha Rock Shelter, Roraima, Brazil

Figure 1.7: a) Unit N95 E101 b) Unit N100, 101 E100 during the campaign 2014 (author: Valle R. B. M.) and c) Trench N97, 98, 99 E100 during the campaign 2019 (author: Cavallini M. S.).

17

Marta Sara Cavallini, et al. During the 2014 fieldwork (Valle 2017), two test pits provided seven calibrated AMS radiocarbon dates, likely related to the human occupation of the shelter. These dates were stratigraphically consistent and spanned from later results around 1200 years BP to 800 years PB (Late PreColonial Period), followed by a Middle Holocene result (4200 years BP), with an older date of 9400 years BP (Early Holocene). Collectively, it suggests three peaks of human activity at the site during the Holocene, with an increase towards the later periods and a clue to the antiquity of its occupation. None of the results, though, could be securely associated with the rock art inside the shelter. Nonetheless, correlations between pronounced differences in the weathering states of petroglyphs, coupled with marked stylistic and technological diversity, are taken to indicate age differences likely connected with the sequence of radiocarbon dates. Tentatively, and as a working hypothesis, those severely weathered geometric petroglyphs of the north-northeast wall seem to correlate with the Early Holocene fire activity prior to 9000 years BP. Those significantly less weathered petroglyphs of the E-SE boulder are associated with the Mid-Holocene fire activity around 4000 years BP.

A phenomenological perspective (Tilley 1994) would consider how that landscape might have been experienced by those who made and used the petroglyphs. In that sense, rock art visibility may become particularly informative. It may also hold a key for paleoenvironmental insight with chronological implications. The visibility of the external petroglyph rocks throughout the surrounding plains and drainages can only occur with open vegetation, like savannah grasslands or caatinga dry forests. During the first campaigns to the site, the whole access trail to the shelter cut through a forested route. When the local community deforested the zone to open pastures, they became aware of the petroglyph boulders in the landscape (Figure 1.8). Although knowing the shelter, the surrounding graphic landscape remained unnoticed, covered by thick vegetation. It follows that when the external petroglyphs were made and used by Indigenous people, the environmental context might have been an open one, not a humid dense forest. Otherwise, their visibility and usability would be impracticable. Back to the shelter, the overload of superimposing layers of severely weathered petroglyphs in the main panel defies attempts to segregate the palimpsest of graphic transformations, following a chrono-stylistic analysis (e.g., Linke and Isnardis 2008). However, differences in weathering states, morphologies, and techniques coupled with distinct spatialities inside the shelter allowed preliminary identification of at least two remarkably different phases of petroglyph production.

These earlier carbon samples, trapped as they were inside the sealed spaces among cobbles at different internal levels of the anthropogenic stone structure, suggest it was persistently associated through time with combustion activities in that same spot, between the E-SE boulder and the N-NE wall and their diverse graphic inhabitants. The shelter sedimentation slowly covered that structure encompassing two archaeological strata (B and C), where fire activities and petroglyph making occurred for millennia. The site and its N-NE panel are dimly lit spots demanding artificial illumination to be adequately seen and used as a work surface. That is why information concerning fire using inside the shelter importantly connects with petroglyph production.

But their analytical potential remains significantly underexplored. Much more needs to be done, beginning with serious conservation diagnosis and 3D laser scanning to fully document the panels and the shelter itself to start a thorough understanding of the rock art. Those poorly lit panels are likely to hold one of the most profound historical sequences of rock art events of the entire Indigenous Amazonia. The taphonomy of long-term Indigenous history encrypted in the N-NE wall may yield a long transformation journey back through the Holocene right into the Late Pleistocene. Excavating the site’s deeper deposits may hold the key to start unveiling such a paramount complexity.

Considering taphonomic, technological and morphothematic similarities between the E-SE boulder sample and many of the external petroglyph rocks in the shelter surrounds, we are hypothetically extending a MidHolocene age to that rock art landscape.

1.5 Concluding Remarks

Paleoenvironmental fluctuations may also carry some burden of causality. That significant change in using the site and effectively building a new cultural landscape may be connected with transformations in the environment. During the Pleistocene-Holocene boundary and over the early Holocene, a dense humid forest likely predominated around the site. In the Mid-Holocene, however, general climatic alterations towards increased dryness south of the Rupununi savannahs (e.g., Behling and Hooghiemstra 2001) may have expanded savannah and dry forest ecosystems up to the outskirts of the Arara Vermelha rock shelter. In turn, this may help understanding how such a change in rock art behaviour, observed in the deep history of the site and its landscape, came into being.

Research on sheltered Amazonian petroglyphs consists of an embryonic exploration with little to no chronometric and contextual data concerning their production. To better approach these issues some archaeologists working in the Brazilian Amazonia have been delving into petroglyphdedicated research. Part of this agenda consists of searching for sheltered petroglyph sites with archaeological deposits available for excavation. These deposits would plausibly contain related production debris, artefacts, or buried panel fragments, indexes that could provide access to petroglyph contextual and chronometric data in the absence of direct dating alternatives (Santos Junior et al. 2018). 18

The Arara Vermelha Rock Shelter, Roraima, Brazil

Figure 1.8: Landscape view of the surroundings of the rock shelter (author: Ednelson Souza Pereira Macuxi), and a boulder with petroglyphs (author: Cavallini M. S.).

As a partial, coarse, and hypothetical biography of the place, we suggest the following: In the final Pleistocene, Indigenous peoples occupying that area started making petroglyphs inside the shelter. Seemingly only in there, secretively, in a secluded place. That way of conceiving and living the site endured for millennia accumulating scars and experiences in the N-NE wall. The shelter became inscribed in the deep myth-history of hundreds of generations. However, in the manner of a Kanaimá place, that is, an avoided and secluded location used for undisclosed ritual purposes of dark shamans (see Whitehead [2002:17-23] on Kuyali ‘ yen cave), it remained apart in that forested rocky hill. During the Middle Holocene, though, things changed. Society, environment, and climate may have experienced transformations towards a dryer cosmos. Then, visitors to the site, inspired by different motivations, started making rock art in the surrounding public rocks, visible in the expanded savannahs. Then, the nature of their relationship with the place, with the landscape, and with the cosmos may all have changed, giving rise to ontological transformations on the rock art itself (e.g., Troncoso 2019).

Likewise, geology, taphonomy, and archaeology converge in the Arara Vermelha to engender a perfect rock art storm. Acknowledgements We would like to thank Dr. Paolo Medici for his kindness, patience and generosity in inviting us to publish this account of our Amazonian rock art research in this important volume. We are also grateful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ), through the research grant process n. 485948/2013-3, and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), through research grant process n. 01419.000026/2019-27 for allowing us the funds to grant the excavation fieldworks at the site. We acknowledge the Museu da Amazônia (MUSA), for the logistic and scientific support, the Museu de Arqueologia e Etnologia da Universidade de São Paulo (MAE/USP), the Universidade Federal do Oeste do Pará (UFOPA) and the Instituto do Patrimônio Histórico e Artístico Nacional (IPHAN) for the institutional endorsement. We also would like to thank to indigenist Ednelson Souza Pereira Macuxi for help with field prospecting and for key discussions, Raul Perigo and Ruan Perigo for excavation assistance and photos, Luiza Vieira for excavation assistance, Emilia Cavallini for additional translation support, and the Rocha Family, the local owners of the site’s rural property, for their constant logistical support and friendly company. At last, but never

Arara Vermelha rock shelter is one of the few petroglyph sites that bring together crucial factors to access Pleistocene rock art in Amazonia. Meteorologists characterise a perfect storm by the rare alignment of climatic and other factors catalysing and releasing extreme amounts of energy. 19

Marta Sara Cavallini, et al. least, we owe gratitude to Dr. Edithe Pereira, from Goeldi Museum, for her constant support to our research over the years, and for lending us the power generator, the light system, and the total station used in the 2014 excavation.

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2 Phantoms on granite: evidence of Iron Age engravings in Western Galicia (NW Iberia) Alexandre Paz-Camaño, Xavier Barros Pereira, Vanesa Mariño Calvo, Eloy Martínez Soto Abstract This chapter presents new protohistoric rock art data found out of hillfort sites in Galicia, NW of the Iberian Peninsula. One of these cases is the engraved panel of A Xesteira 8, which shows a scene of a horse with rider. The composition of the scene was created by overlapping figures. The Galician open-air rock art is mainly made on granite. The rough granite surface shapes the visual appearance of the engraved panel and, consequently, their recording. We perform a record of the rock art panel by employing digital photography and photogrammetry, complemented with a geological survey of the stone. The geological analysis on granitic etched surfaces allows us to cast new light on Galician rock art studies. Keywords Rock Art – Geology – Digital recording – Iron Age – Horse 2.1 Introduction

we used Structure-from-Motion (SfM) photogrammetry. This recording process is a non-intrusive system, using photography to capture the light and orientation of the pictures.

This work approaches an anomalous type of Galician rock art which could be related to the Iron Age period. The main objectives of this work are to make a geological, photographic and photogrammetric recording of the engravings and describe the rock art panel of A Xesteira 8. Starting from the rock surface visibility conditions and the characteristics of the rock, an investigation of the engravings was undertaken in three different ways: the rock art panel (geology), the morphology of the rock surface (3D), and the perception of the motif engraved (2D).

Galicia is a region located in the northwest of the Iberian Peninsula and neighbouring Portugal. This territory is known for its numerous sites of open-air engraved rock art sites, currently estimated at around c. 3374 rock art panels, which date from Prehistory through to the mediaeval period (Rodríguez et al. 2018, 111). The themes represented in the rocky outcrops include geometrical figures as circles, lines and cup marks (Peña and Rey 2001, 33; Peña 2005, 18). Other figurations represent animals, humans, weapons and other less numerous figures – such as ships, idols, or engraved mills - (Peña and Rey 2001, 41).

The surface and grooves of the rock were analysed geologically to help understand the working surface state and its characteristics. Considering the engravings made on granite rocks, the topic of overvaluing the weathering effects on granite and then in engraved stones has frozen the progress of rock art studies in Galicia (Vidal et al. 2018). Another important aspect was to recover volume information of the stone and grooves, and for this proposal

In neighbouring Portugal, in the Côa valley, several examples of Iron Age rock art were documented inside and outside settlements (Abreu et al. 1999; Baptista and Reis 2009; Neves and Figueiredo 2015; Figueiredo et al. 2016; Luís and García 2008; Luís 2008, 2009, 2010, 2016; Alves and Reis 2014; Reis 2011; Santos et al. 2012; Silva et al. 2016) (Figure 2.1). In Galicia, we have two fortified Iron Age settlements with protohistoric engravings discovered during excavation campaigns, and chronology backed by the archaeological context (Figure 2.1): Castro de Formigueiros (Samos, Lugo) and Monte do Facho de Donón (Cangas do Morrazo, Pontevedra)1.

 In some Galician hillforts there are other samples of rock art that could be related to the Iron Age with engraved figures of snakes. Those examples are inside hillforts in the province of Pontevedra and represent snake figures: Castro de Penalba (Campo Lameiro), Castro de Troña (Ponteareas) and Castro dos Remedios (Moaña) (García and Peña 1980). 1

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Alexandre Paz-Camaño, Xavier Barros Pereira, Vanesa Mariño Calvo, Eloy Martínez Soto

Figure 2.1: Rock art sites with engravings related to iron age in Northwest Iberia: 1.Val do Côa (Guarda, Portugal); 2. Castro de Formigueiros and 3. Monte do Facho de Donón (Galicia). On square, survey area and location of A Xesteira 8 rock art site. Below: Some engravings found in hillforts of Formigueiros –A, fish and B, horse- (Meijide et al.2009) and Monte do Facho –C, engraved cylinder and D snake shape over a granite slab-.

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Phantoms on granite The hillfort of Formigueiros, located in inner Galicia, has different representations; these cases are incised on slate slabs located between dwellings of the settlement (Meijide et al. 2009). These engravings exhibit horses, fishes, triangles and circular and labyrinthine designs (Figure 2.1). In Monte do Facho de Donón, two other examples of engraved art on granite were discovered, spatially related to a circular building and related to the use of this space in Proto-history (Suárez 2008, 300-303). The first example is a worked stone cylinder of granite located in front of a possible entrance and inside the vestibule of the structure. It has grooves on its surface, two eyes and other parallel lines on the upper section. The other example is a small slab of granite that is part of a platform structure located inside. The slab has an engraved snake created with a zig zag line (Figure 2.1).

8, the design of the horse uses two lines to create the body plus two more for the legs (Figure 2.2). The upper traces form the neck, the back and the hindquarters. The bottom line also forms the neck, a marked chest, the belly and the other hind leg. The front legs are added to the body by adding two more lines from the chest below (Figure 2.2). The figure of the horse is defined by grooves with an irregular width that varies between 5 mm and 19 mm, and depth that varies between 3 mm and 8 mm. In some areas the grooves present ripped and fragmented edges, which refer us to the tools employed on the execution of the figure. Another animal figure appears to be attached to the neck and belly of the horse (Figure 2.2 right). The body of this figure is made up of the belly contour of the horse and another shallow line below. Different traces in this shape are superimposed on the horse´s grooves.

2.2 The engravings of A Xesteira 8

The problem with these shallow grooves is the tendency to be over lighted. Thus, a complete vision of the figures is difficult from only one point of view or using a single lighting position.

Our area of survey is located on the southern side of O Morrazo, in western Galicia, province of Pontevedra. O Morrazo is a peninsula 10 km wide and 40 km long with a NE-SW orientation, that is characterised by an orography surrounded by the Ria of Vigo and Ria of Pontevedra. O Morrazo is an arm of land articulated by a central ridge that divides the southern and northern slopes; subdivided by different mountain ranges that create regions and valleys.

The group of thin and intermittent lines over the horse’s back schematized a rider. The legs are engraved in two opposite arcs over the horse´s engraved layer. The upper body of the rider figure is blurred by the addition of a circular shape with superimposed lines on his torso that resembles a shield (Figure 2.4, low image).

A Xesteira is an open-air rock art site with eight engraved panels of cup marks, a circle with cup-marks inside, concentric circles, strokes, lines and two animal shapes. One of the figures, a horse, is located on the panel named A Xesteira 8 (Meira, Moaña), which measures 95 cm on the N-S axis and 160 cm on the E-W axis (Figure 2.2). The most discernible engraving is placed on the middle of the panel. This sample includes an equine figure. The horse shape is constituted by abnormal morphology compared to other representations of horses in Galician prehistoric petroglyphs (Peña 2005, 26). They are usually formed by one or two continuous lines. When the silhouette of the animal uses two lines, each of the lines constitutes the upper and lower part of the horse. In the case of A Xesteira

On the rest of the panel of A Xesteira 8 we can distinguish fragments of other motifs, such as circles or groove sections. Furthermore, we can see traces of work in the modification of the initial volume of the stone outcrop. The granite panel is modified to what appears to be shaping a horse, by lowering specific areas of its surface. This bas-relief work is prior to the layer of the horse and the rider engravings (Figure 2.2 and figure 2.4). This work of removing stone material is most apparent in the right of the upper quarter of the panel. The neck and head of the horse relief is created by removing a triangular area contiguous to the geologic fracture in this part of the panel.

Figure 2.2: Right: A Xesteira 8 panel with oblique lighting. At centre of panel, horse and rider figure. Left: Animal figure attached below line of horse’s body. See the texture of surface due to the height of the quartz/feldspar grains.

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Alexandre Paz-Camaño, Xavier Barros Pereira, Vanesa Mariño Calvo, Eloy Martínez Soto Considering the technical aspects of the execution, the tool marks left by a quartz pick and recovered in experimental archaeology (González 2020, Otero 2020) are different to marks left in this rock art panel. As such, the engraving of horse A Xesteira 8 was probably made with a metal instrument by the short width of grooves – more difficult to reach with quartz picks – and the presence of loose and deep pits in stone surface. Those pits have a low diameter and are deeper in comparison with another made with quartz picks. Quartz picks and chisels have some limitations due to the mineral structure and impact resistance. Due to this, it is believed that direct percussion over the surface was used in Galician prehistoric rock art (PAAR 2011). Indirect percussion is possible but increases the risk of chisel breakage because quartz has cleavage lines that are activated by bipolar percussion.

feldspar grains and the geomorphic approach can be useful to the photographic analysis of the engraved panel. Thus, the surface of the engraved panel is reviewed for diagnosis and here geology becomes essential to comprehend characteristics and micro topography in the context of Galician open air rock art of the studied area. 2.3 Geological analysis of the surface In northwest Iberia, the most remarkable geological formation is the Iberian Massif. This massif represents one of the largest size outcrops of Variscan Mountain Range2. The survey area matches with Galicia-Tras-Os-Montes geological zone inside the Iberian Massif3. Galicia-TrasOs-Montes is a geological territory with tectonic, structural and metamorphic features which are different to the Centre Iberian Zone. It is also characterised by rocks of oceanic nature and metamorphic events developed under high pressure, related to subduction processes. Focusing on our studied area, the Variscan Orogenic episode comprised the intrusion of different kinds of granitic rocks4 that include granite and biotite granodiorite, granodiorite with feldspar mega-crystals and alkaline feldspar granite. This intrusion of igneous rocks caused the transformation of previous sediments and rocks into metamorphic materials (schist and gneiss) as a result of the Hercynian cycle.

In reference to the perceptive aspect several problems arise when analysing the engravings, as many of them are eroded or camouflaged. Likewise, being able to discern a figure could be related to factors such as visual interference, lighting, micro-shadows, superposition of lines and, to a great extent, the texture of the rock, its relief and micro topography or heterogeneity of the grooves used to compose the engraving. Regarding the visibility of the engraved motifs, the referents in this area are prehistoric or historical examples which show grooves made of deep lines with a clear shadow. In addition, the geological characteristics of the granite outcrop configure a favourable scenario for camouflaging, because of the background heterogeneity due to the variety of colours from different mineral grains.

2.3.1 The granite studied in Xesteira 8 panel Structure The engraved panel of Xesteira 8 is composed of alkaline feldspar granite (Figure 2.3). Despite the presence of lichens, which attenuate the colour effects on the most part of the rock surface, its vermilion colour is dominant. The rock art panel has a mineralogical composition similar to granodiorite, but excluding the presence of plagioclase, more content in potassic feldspar (K-feldspar) and less quantity of biotite. The size of the grain is medium in general, while the grain tends to be equi-granular on

The visual interference is another factor that hinders the panel’s perception. In a groove, the lights and shadows are essential for its comprehensibility, but in our example, light points and sharp shadows (micro-shadows and illuminated points) make it even more difficult to analyse the figures. This is mainly because of the confusion between the characteristics and weathering of the support (texture), the engraved areas (types of grooves), and in some cases the overlapping traces and shapes.

  It was formed due to the collision of Gondwana and Laurasia continents 300 million years ago (Rubio 1997, 3). 3   The geological zone Galicia-Trás-Os-Montes was defined recently, it was not until the end of the 1980s that it was individualised. Previously it was part of the Central Iberian Zone (Julivert et al., 1972), but Farias et al. (1987), and Arenas et al. (1988), proposed the existence of a new zone, the contact between both areas is a great ride that superimposes the Galicia-Trás-Os-Montes area to the Central Iberian one. The authors cited above also proposed a subdivision of the new area into two structurally overlapping domains: Domain of Galicia-Trás-Os-Montes in the lower part and Domain of the Allochthonous Complexes in the upper part (Vidal and Grandal 2016, 8). The Xistoso domain is currently an integral part of the distant margin of Gondwana transported tectonically to inside areas of the continent (Arenas et al. 1986; Farias et al. 1987; Martínez et al. 1999). In lithological terms, it is mainly made up of metasedimentary and metavolcanic rocks of a felsic nature. 4  According to a recent scenario about the origin of Variscan granites, Pastor et al. (2013) develop the idea of terrestrial super volcanoes whose magmatic substances arose because of subduction of Gondwana under Laurasia. That process happened in Variscan orogenic episodes, from late Devonic to final stages of Carboniferous. Granites of today would be in fact the roots of proposed super volcanoes consolidated at 20 km of depth. By the genesis of Galician granites, we had explained, they are classified as class “S ‘’ granites according to Chappell and White (1974). 2

Finally, the volumes and the micro-topography of the surface make it difficult for the artificial lighting techniques to illuminate the whole panel in a homogeneous way. This impedes a clear visibility and the accurate reading of the figures engraved on stones. If we look at the surface of an engraved panel from a geomorphic point of view, we can see a micro-landscape generated by differential erosion. The original surface of the rock was cut by the grooves as if they were valleys and canyons. The addition of more lines in different directions cuts the surface on different pieces of the original outcrop. The resulting surface, due to its composition and evolution during the time, has resulted in a volumetric loss. Furthermore, due to the high resistance of the grains of quartz and feldspar the reliefs endure. These quartz/ 28

Phantoms on granite

Figure 2.3: Geological survey areas perceived on potassic granite surface of A Xesteira 8 panel.

contact areas. Finally, we have the biotite aligning phase, which corresponds to an episode of thermal deformation during an orogenic mechanism, presumably by intrusion of a medium-grain granitic rock.

pattern. This net of fractures represents several weakened areas of rock structure and likewise it could be the origin for new weathering processes. These processes could substantially change the physical and chemical morphology of the rock.

Regarding the stone colour, the panel presents, as one of its main features, a central area with red colour (Figure 2.3 second area). The red hue varies from 5R 5/4 to 8/8 in the Munsell colour chart (Munsell Colour Co. 2010). This red hue informs us that there is a potassium abundance (K2O) with a volume close to 30%. Thus, with a high probability, the granite mass had been secondarily altered by hydrothermal fluid one time cooled. That process could explain quartz dilution and potassium increase on this granite.

In the case of A Xesteira 8 the examined and surveyed stone does not present any apparent fracking nets, but is a fragment of a bigger intrusive mass which had to be dismantled a long time ago. The granite presents a lightly altered surface resulting from its natural exposure to climate conditions during millions of years. The Xesteira 8 rock art panel is a flagstone with polygonal shape, and the stone rests on a lower outcrop (Figure 2.3). A shearing plane is visible on the lower part of the stone where no evidence of stone cutting marks was found.

On the right side, the boulder presents the surface altered (Figure 2.3 third area). The interpretation to this could be the physical weathering caused by haloclasty, which could be explained by the nearness of the archaeological site to the sea. In medium grain granite the sea salt enters the rock through pores. The salt precipitates there, and increases its volume causing press pore breaking stone material on a millimetre scale. As a result of that process, we see a surface roughness and a prominence of the most resistant mineral grains as in the case of quartz. This mineral has enduring quality, resistance and therefore indicates the maximum preserved heights of the original surface.

The stone of Xesteira 8 shows a high level of structural resistance to deformation. The engraved panel has neither faults nor notable oxidation areas on the surface. On closer examination, the rock shows a partial oxidation of its minerals, especially biotite, with a localised distribution that does not affect the general structure of the stone. As previously mentioned, the stone does not show any fractures of the net, neither orthogonal, polygonal nor horizontal. Also, we do not account for other samples of weathering effects that are typical on granitic landscapes, such as gnammas or gutters (Vidal 1989, 101). The visible surfaces of the panel look worn, which indicates that the local rainfall is to some extent also important, and has affected the chemical weathering of the surface.

Surface and structure alteration The granite rock usually alters due to the existence of discontinuities, either isolated or following a regular 29

Alexandre Paz-Camaño, Xavier Barros Pereira, Vanesa Mariño Calvo, Eloy Martínez Soto Natural light recording

At the level of structural alteration, the most striking feature is the contact limit zones but these do not represent a marked effect on the structure of stone, being the usual evolution of natural agents on the rock.

A photographic survey was taken with natural light and different humidity degrees in 2017 and 2018. The most balanced results were obtained on wet and cloudy days but also when the light is softer and more diffused. This helped to homogenise the lighting on the rock surface and catch general views without interference of the shadows of the surrounding vegetation.

Apart from the surface roughness area mentioned above, we also see that there is a fracture line between the third and fourth area (Figure 2.3), which was a fragility rupture. In addition, there is a sequence of subverted channels in the second area (Figure 2.3). This might not be caused by differential erosion, as there are no relevant differences in the mineral hardness of this alkaline granite. In such a limited area of alteration, the idea of weathering due to rainwater is also inconsistent, as the channels are in a very specific zone and have no continuity in the rest of the support. The loss of volume in the right upper quarter could be derived by weathering process or anthropic activity. It is however difficult to specify what factor was the most determinant one, as the information recovered in the field might point out a combined action of several kinds of alteration. However, we believe it is more likely to have been an anthropogenic alteration of the rock.

Artificial light recording Artificial lighting was specifically used to focus on the engraved motifs. For this task, portable spotlights and LED bars were used. We used 60-Watt white light LED lamps at 170 lumens. The results improved the distribution of the light by making it more homogeneous. In the case of the 10-Watt and 20-Watt portable spotlights, they emit more intensity of light but are more concentrated. While this caused parts of the stone surface to be overexposed it was possible to obtain information about the relief of the support (Figure 2.4).

2.4 The Digital Recording of Engravings in A Xesteira 8

The points and angles of light incidence play a fundamental role in the system of documentation as the grooves differ in width, depth and orientation. Hence, we implemented the use of colour gels in lamps of lighting and flash. Gels have primary colours5 in order to discern orientation areas from the surface. That is a similar approach to the relief orientation charts in cartography. The combined use of two opposite spotlights with coloured gels allowed us to recover more information about the surface in one camera shot (Figure 2.4), differentiating between the coloured walls of the furrow and the deep´s furrows shaded. The results of this method provide valuable information for the analysis of stone surfaces. Also, the captures with coloured lighting allows for the possibility of finding other markings.

Currently studies of engraved rock art rely on lighting, the morphology of the stone or the biotic colonisation of the surface by lichens. Since the 19th century, many different systems of tracing have been tested to study engraved panels, such as manual drawings, raking light, photographs, frottage, etc. (Domingo et al. 2013, 79). At the end of the 20th century, the introduction of digital technologies radically changed the recording methods, providing a wide range of resources and tools for the archaeologists and facilitating non-invasive documentation techniques (Domingo et al. 2013, 21). Within our work we combine photography with SfM photogrammetry, as a system for 2D and 3D recording and analysis of the engraved panel.

Digital analysis

2.4.1 The photographic recording

Digital images not only collect quantitative data – e.g., the percentage of light or reflectivity – but also other information of the photographed space. The capture of spatial data allows to study the rock art by using image processing analysis over the photographs. In the case of painted rock art, the usefulness of colour decorrelation treatments and false colour images (Pereira 2012) as well as the analysis of the main components of image is recognized (Rogerio 2013, 55-57).

Digital photography was used for two-dimensional rock art recording as it was easy to transport and is non-invasive. The photographs were taken with a digital SLR camera (24.2-megapixel resolution) and two photographic lenses (AF-S 18-55 mm and 50 mm). Flash and lights with colour gels were also incorporated for nocturnal recording. The photographs were taken in JPEG and RAW output formats. The JPEG format was chosen for its reduced digital weight and RAW for several experimental shots seeking greater details. The camera was located in a zenithal position and on an orthogonal view to the rock surface.

The introduction of digital technologies at the end of the 20th century brought a wide range of software and technologies to capture, retouch and digital treat of images. Digital tools have been employed to record painted and   Blue, magenta and yellow were the most used colour gels. In areas with two coloured lighting beams this method has as result the differentiation of these areas by mixing of light colour. In this approach we have used a polycarbonate-coloured filter for a zenithal flash, too. Combined use of opposite-coloured spotlights in addition to coloured flash light allows recovering relief orientation data from the surface. 5

The recording of the carved panel was performed on a multi-method scale, experimenting with natural light exposure (direct sunlight, diffuse light or wet rock), and artificial raking lights at night. 30

Phantoms on granite

Figure 2.4: A. Left: Photogrammetric model with Lambertian shading (up) and areas of modified volume of stone surface to create a horse shaped support (below). Right: Views of the panel with oblique lighting from east/west side shading areas of modified volume of the surface. B. Detail of engraved surface with two opposite lighting axis and gel filters. C. Drawing of the shapes identified on central engraved area of panel.

engraved rock art in the Iberian Peninsula (Domingo et al. 2013) and painted rock art at the last decade in Galicia for decorrelation (Alves et al. 2017, fig.13; Comendador 2020a, 2020b; Lombera and Fábregas 2013; Rodríguez et al. 2019, fig.7 and 8; Tejerizo et al. 2020; UVigo 2019) and for digital tracing (Rodríguez et al. 2018, fig.6). Digital image processing and enhancement of engravings was also used in the treatment of scanned frottage (Fábregas and Rodríguez 2012, fig.11).

survey digital images looking for specific colour tones with the help of image editors and apply spatial analysis to understand the distribution of light and colour hues.

In the case of the engraved granite panels, the colour of the rock has little difference in appearance between the background and the grooves. In addition to this is the camouflaging effect of the smaller alignments caused by the mineralogy of the rock. The reason for this is that an image over a monochrome background allows a better appreciation of the shapes rather than on a polychrome and asymmetrical (in colour) background. Despite this, it is possible to partially enhance the engraved areas. We have used image editing software for this purpose. The images could be equated to cartographic documents where spatial and topographical information are represented by coordinates and thus, they could be treated with GIS tools or 3D analysis of micro topography (Jalandoni and Kottermair 2018; Melard 2010). The digital image is also a pixel matrix with different numeric values corresponding to the surface´s reflectivity and different wavelengths (Rogerio 2013, 55; Sabins 1987).

SfM photogrammetry allows the production of 3D models from photographs taken with an ordinary camera which is especially beneficial if we take into account that the great majority of Galician rock art is found in areas with difficult access. These factors would complicate the data gathering using other more expensive and less portable methods, such as laser scanners.

2.4.2 The photogrammetric recording Using a three-dimensional record method is one of the most accessible options for investigating the rock art panels.

Furthermore, the progress made in computer graphics in virtual representation of etched surfaces has opened new pathways to improve the recording of petroglyphs that had previously been undertaken using other techniques such as recording by contact, like frottage or tracing with plastic (Seoane 2009). The 3D models of the engravings were created with Agisoft Photoscan 1.3. This software allows the generation of a 3D point cloud from the photographs, creating a mesh with geometry that is later given a photorealistic texture (Figure 2.5). Two other types of software were used for the rendering and post-processing of three-dimensional

On granite engraved surfaces, the colour of stone grains will combine with received light. Due to this, we can 31

Alexandre Paz-Camaño, Xavier Barros Pereira, Vanesa Mariño Calvo, Eloy Martínez Soto

Figure 2.5: A. Camera positions from the photogrammetric surveying in A Xesteira 8. B. Digital elevation models (DEM) with level curves. C. 3D model sections of panel:  zenith view with section line; below, profile of the section of the rock. D. Postprocessed photogrammetric model using RadianceScalling & LitSphere. Detail of horse figure.

(Figure 2.5). The 3D model was later analysed in Meshlab and Blender in order to produce renderings of the threedimensional mesh with virtual illuminations of the enhanced motifs allowing for better images of the motifs. This virtual illumination allowed us to simulate the process of nocturnal illumination of the panels and establish an infinite series of illumination points simultaneously (something which is very complicated to replicate in a field work campaign). This virtual illumination greatly improved the multiplicity of interpretations in the process of decoding the iconography.

models: MeshLab and Blender 2.7. Both of which allow the user to create renderings of the 3D models with photorealistic texture and better define the engraved surface of the rock panel. Regarding the different photogrammetric techniques, we used SfM photogrammetry for documenting the engravings rather than others such as Reflectance Transformation Image (RTI)6. For the latter the camera must be static in the capturing process, therefore this limits the variety of perspectives necessary to document the etchings found in this investigation with the utmost precision.

The post-processing analyses applied over the 3D mesh provided very interesting results regarding the etchings visible in the panel. In order to highlight the grooves, we applied two post-processing filters in MeshLab, such as Radiance Scaling and Lit Sphere RS (Figure 2.5). These techniques have been widely applied in Galicia over other rock art case studies (e.g., Vilas et al. 2015).

The panel at A Xesteira 8 had been previously documented in detail, by means of daily and nightly observation and photography. In this research we decided to work less with photorealistic 3D models as the former are difficult to handle on conventional computers when compared to three-dimensional meshes. Afterwards, the models were digitally scaled for the creation of the digital models

The application of these filters allowed us to highlight the existing grooves on the rock by applying two spheres on the 3D model that codify the light, thus, highlighting the differences between its cavities. The main virtue of this kind of highlighting is the simplification of the etchings in the rock, allowing a simple viewing and a clear distinction

 This technique consists on capturing a sequence of images -always from the same position without varying the angle-, with the corresponding changes in the position of the light source from some spheres that have to be included in the scene, as a point from which the light source starts through its reflection (Carrero et al. 2015) 6

32

Phantoms on granite of these motifs. However, this also points out an important problem, such as the loss of definition when the 3D model was created. This problem aside, the technique allowed us to obtain preliminary results almost instantly, which greatly reduces the time needed to define the etchings using other techniques, such as frottage.

with respect to the elevated surface illuminated by the opposing spotlights. The photographic recording also allowed us to get very accurate 3D models, which provides information about the topo­graphy of the stone of A Xesteira 8 and the volumes of bas-relief horse. The photogrammetric processing allows seeing the difficulty of carrying out lighting surveys on the field.

Some of the rock engravings, however, happened to be more difficult to read. For these in particular we used other types of post-processing filters, such as Minnaert (similar to V-RTI) (Elorza et al. 2014). This technique allows the visualisation of the etchings with uniform shading, in such a way that the renderings are not “contaminated” like with other types of post- processing filters, which try to simplify the iconographic data. In this way, the tridimensional mesh seems to have a metallic appearance (Figure 2.5), while it clearly maintains the imperfections of the rock, with the possibility of incorporating lighting points to illuminate the 3D model. This technique is very useful to verify the existence of less accentuated grooves in the rock, which are barely noticeable to the human eye, something that can be approachable by other methods, such as Radiance Scaling or AsTrend (Carrero et al. 2016).

Concerning the engraving technique, the tool marks detected in A Xesteira allow us to conclude that the horse and rider motif could be ascribed to the Iron Age period, this being based on the morphology, iconography and execution of horse figure and rider. The marked chest and curved neck of the horse and head position reinforce the differences with other representations of this animal in Galician rock art. The rider presents a contour made with double line and not by etching a groove as other examples. In addition, the shield is circular and this typology had presence on northwest Iberia from Bronze Age (shield with V-shaped recess) to Iron Age (caetra). These characteristics are those that point us to the relationship with the Iron Age. The relief under the engraved layer could be speaking of re-utilisations of nearby periods.

Both models present high-quality metrics, with more than 3 million points. This way, the existing measurements can be obtained with utmost precision. The degree of definition of the geometry of the 3D models is of great quality. This is how we are able to observe every grain of quartz on the surface.

Finally, as exemplified from this work, we think that a detailed review of the Galician granitic outcrops would increase the current open air rock art inventory. Indeed, other doors could be opened for the Galician open air rock art, joining efforts between geology and archaeology, by removing misconceptions based on comparison with sculpture from the Middle Ages and the effects of weathering in those carved stones.

2.5 Conclusion After examining the structural, morphogenetic and geochemical characteristics of the granite panel in detail we can conclude that the carvings of A Xesteira 8 panel did not have remarkable influences from events of geological nature, the surface of the stone has high geologic competence. In A Xesteira 8 panel the original morphology of the stone surface was lowered to create bas-relief of the horse in the background. This is a novel example of sculptured work on the Galician rock art. In addition, we check the existence of fine engravings which are usually not considered in the recording process because of their small size or discontinuity. The presence of overlapped layers of engravings over bas-relief, will allow a stratigraphic survey by figures.

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The digital recording of the stone of A Xesteira 8 in 2D and 3D also offers us important information about volume and relief. The 2D photographic recording produced a wide variety of different image products, such as those from the lighting using two and three axes of coloured light, the reflection of surface (zenith coloured flash) or image analysis products. The use of coloured lights with primary colours in opposite positions provide us views of the surface where the orientations of micro-topography helped to understand the surface and record more information in a shot. In addition, the use of a third axis of light in a zenithal position reinforces the marking of the deep areas

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Seoane, Y. “Propuesta metodológica para el registro del Arte Rupestre de Galicia”. Cadernos de Arqueoloxía e Patrimonio 23 (2009): 18-20. Silva, A., Xavier, P. and Soares de Figueiredo, S. “As gravuras rupestres de Crestelos (Tras-Os-Montes, Portugal) e a súa longa diacronía desde a Idade do Ferro ao periodo contemporáneo”. In Estudo de Arqueoloxía, Prehistoria e Historia Antiga: Achegas dos novos investigadores, edited by R. Cordeiro Macenlle and A. Vázquez Martínez, 63-81. Santiago de Compostela: Editora Andavira, 2016. Suárez, J. “Monte do Facho, castro ou santuario?: A campaña do 2008 e a arquitectura sacra na cultura castrexa”. Portvgalia 36 (2008): 295-312 35

3 The prehistoric open-air sanctuary of Penedo do Ferro (Monforte, Portugal) Leonor Rocha, Paula Morgado Abstract During the present research project, in the area of Monforte (Portugal), from the responsibility of the signatories, we identified an open-air sanctuary with rock art. Here we present the Penedo do Ferro´s settlement, where a significant set of rock art was identified in small shelters and isolated rocks, around the settlement which corresponds to a large prehistoric open-air sanctuary. Therefore, the aim of the work will be to show how the use of photogrammetry techniques might help to provide better documentation in rock art studies. Keywords Rock art – Photogrammetry – Penedo do Ferro – Monforte – Portugal 3.1 The Study of Rock Art in Southern Portugal

It seems this subject was rapidly forgotten in Portuguese research until the late 20th century when, on the upper (exterior) part of the only cave in Portugal identified as having cave paintings, Escoural Cave (Montemor-oNovo), where there was also a chalcolithic settlement, a “sanctuary” with horizontal engraved panels was identified (Gomes et al. 1993). It was also at this time that more systematic identification studies began, along with the study of other types of rock art, namely the open-air type associated with major rivers (the Tagus and Guadiana), megalithic monuments, or on isolated rocks dispersed in the landscape (Baptista and Martins 1979; Gomes 1989; Calado 1997; Calado and Bairinhas 1994).

Rock art can be found throughout Portugal, with some regional differences in terms of media, themes and representativeness. The oldest known mention of a rock art site dates to the 18th century and concerns an engraving on a cliff known as “As Letras” (“The Letters”) at Cachão da Valeira, by the River Douro. It was destroyed in the 19th century, when the Douro railway line was built (Contador de Argote et al. 1734; Correia 1916a, b) In the Alentejo region, the first studies and records of rock art appear in the early 20th century, with the identification of painted art at Esperança (Arronches) and open-air engraved art at Mora and Arraiolos (Breuil 1917; Correia 1916b, 1921). Vergílio Correia wrote in 1916 of these extraordinary new findings, saying that a new field of study was emerging for researchers of prehistory in Portugal (Correia 1916b, 158). It was at this time that several studies aimed at identifying rock art (painted or engraved) in this region began, although not on the scale Vergílio Correia envisaged (Correia 1921).

In the early 21st century, the Guadiana group of rock art was identified, in the region around the Alqueva Dam, along with other groups of engraved rocks, like Penedo do Ferro. They appear to constitute natural open-air sanctuaries, some associated with settlements, others in landscapes with a high symbolic value, such as river valleys and monumental outcrops. The study and assessment (or reassessment) of this group of rock art in the Alentejo has been the subject of specific research projects, which have resulted in the publication of numerous articles and theses (master’s and doctoral) (Alvim 2009; Alves 2003; Baptista 2009; Baptista and Santos 2013; Bueno-Ramírez et al. 2015; Calado 2004; Calado and Rocha 2010; Cerrillo Cuenca et al. 2019; Ferraz 2016; Martins 2014; Rocha 2004, 2010, 2013, 2016). However, most of these sites have had studies with traditional methodologies (Gomes et al. 1993; Calado 2004; Calado and Bairinhas 1994; Oliveira and Oliveira 2012) and only in the last decade did photogrammetry and 3D survey work begin in the south of Portugal. The use of these photographic techniques represented an important advance in the interpretation of some of the most important prehistoric sites in this region, especially of megalithic art (Bueno-Ramírez et al. 2015; Cerrillo Cuenca et al. 2019; Ferraz 2016) 37

Leonor Rocha, Paula Morgado 3.2 Geographic and Archaeological Setting

located to the east, south and west of Penedo do Ferro (Figure 3.2) (Rocha and Morgado 2018). Approximately 350m to the east, another shelter and an isolated granite monolith with rock art (small cup-marks), evidence of a Neolithic settlement, and vestiges of more recent periods, namely Roman, have been identified.

The Penedo do Ferro settlement is located on an elongated knoll that lies in an east west direction at an altitude of 350 m. It is surrounded by granite outcrops and has good visibility over the surrounding area. The area stands out in the landscape not because of its high elevation, but because it is located in a very flat area and because of the granite outcrops, which command attention even today (Figure 3.1).

3.3 Field and Laboratory Work: Methods Our study focuses on a group of seven panels of rock art engraved on granite outcrops, located around the Penedo do Ferro settlement. These engravings, consisting of small cup-marks (of different dimensions and depths) and grooves, are located on isolated boulders or at the base of small shelters.

The protohistoric settlement was established on the upper part of the knoll and in some places the remains of structures can still be seen. Furthermore, in some locations the outcrops were used as walls, which may have contributed to some rock art being concealed (Gomes et al. 1993).

The studies we intended to carry out on this group included different tasks, aimed at a comprehensive characterization of this sanctuary. Unfortunately, during the course of our research, the owner cancelled access to the site, and in accordance with Portuguese law, we cannot carry out research work without the required permit.

At its base, some probable Neolithic sites have also been registered. Their relationship with the sanctuary is almost certain, considering not only the chronologies put forward for this type of rock art but also the relationships between these and two types of vestiges in other areas (Rocha 2004, 2010).

The fieldwork completed to date thus consists of:

The prehistoric sanctuary consists of a group of seven small nuclei installed in shelters or on granite boulders,

1. Identification of the rocks with engravings (Figure 3.3). Note that to this end, it was necessary, in some

Figure 3.1: General view of Penedo do Ferro protohistoric

38

The prehistoric open-air sanctuary of Penedo do Ferro places, to clean the surface of the rock because the presence of moss or lichens compromised the correct visualisation of all the engravings and the quality of the visual records we intended to make. As it was not possible to carry out another round of fieldwork, there may still be some engraved boulders not identified by the team during the first phase. 2. Georeferencing (GPS) and brief description of all the panels. 3. Daylight photographic survey of each panel for the purpose of photogrammetry. There were also some problems with this phase, which were only identified when the pictures were being processed in the laboratory (the angles of some parts of the panels weren’t clearly characterised and required further photographs). In terms of methodology, we tried to follow the basic procedures for data collection, such as maintaining the distance between the photographic equipment and the rock surfaces to avoid distortion of the perspectives or the motifs. The photographs were processed using Adobe Photoshop and Adobe Illustrator in the initial visualisation and verification of all the photographs taken so as to eliminate any that were out of focus and make other improvements. The second phase consisted of processing the photographs with Agisoft PhotoScan in order to obtain a threedimensional view of each panel. This 3-D technique allowed us to obtain a full visualisation of the panel’s surface.

Figure 3.2: Location of engraved art at the Penedo do Ferro Sanctuary (CMP 1:25000, Fls 399/413)

Figure 3.3: Prospection work: identifying engraved outcrops

39

Leonor Rocha, Paula Morgado Panel I

The final modelling was worked on to obtain a decal of the existing engravings. Lastly, the engraved motif images were processed with Adobe Illustrator.

Located in a small shelter, open to the north, on the southern limit of Penedo do Ferro, with visibility over the Neolithic settlement. It features dozens of cup-marks, of different sizes, made on the floor of the shelter (Figure 3.4). On the floor of the shelter 5 larger cup-marks each surrounded by dozens of smaller sized ones are visible. Another small shelter, about 1.5m deep and 1.5m in height, can be seen to the east. Dimensions: 2m high x 2,20m wide x 2m long.

3.4 Description of the Panels As mentioned earlier, the number of panels identified (7) may increase if new fieldwork can be carried out (Rocha and Morgado 2018). In all the cases the representations were derived from direct percussion, as in the other cases known in the south of Portugal. In fact, cup-marks are one of the most common themes in the Portuguese bibliography, although there are no specific and in-depth studies on this topic. Cup-marks appear in different types of rocks (granites, schists, etc) and at different types of sites: settlements, menhirs, dolmens or in scattered outcrops in the landscape. Moreover, they are diverse in their grouping and size. Their systematic association with prehistoric contexts suggests they may have been made in that period (although some may possibly be from a later date). In some cases, such as Penedo do Ferro, their association with shelters and typology could imply that they may have been religious sites (Calado 2004; Calado and Bairinhas 1994; Calado and Rocha 2010; Correia 1921; Gomes et al. 1993; Leisner and Leisner 1959; Oliveira and Borges 1998; Oliveira and Oliveira 2012; Rocha 2004, 2010, 2013, 2016).

Panel II An isolated, flat, oval-shaped granite boulder with at least 16 cup-marks some of which are connected (Figure 3.5 and 6) is located on the eastern edge of the settlement. This boulder faces north towards the platform where the Neolithic settlement is located. Dimensions: 1.30m high x 1.60m wide x 0,70m thick. Panel III Panel III is located on the SW edge of the settlement and consists of two isolated granite boulders approximately 2m apart. The levelled area faces the Neolithic settlement. Boulder I: features 15 cup-marks at the top. Dimensions: 0.70m wide x 1.60m long.

Figure 3.4: Panel I – General view of the shelter

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The prehistoric open-air sanctuary of Penedo do Ferro

Figure 3.5: Panel II – General view of one of the engraved boulders

Boulder II: features 4 aligned cup-marks and one groove at the top, which is slanted. Dimensions: maximum height 1.40m x 2.70m long. Panel IV An isolated granite outcrop on the SW side of Penedo do Ferro at the base of the wall 4 cup-marks are found at the top and at least 7 on a slanted surface facing SW. Panel V A small, isolated granite boulder on the SW side of Penedo do Ferro at the base of the wall. It features 7 shallow cup-marks. Panel VI Granite outcrop next to a holm oak located on the SW side of Penedo do Ferro at the base of the wall. It is located approximately 5m to the NE of Panel V and features 8 cup-marks facing NE. Panel VII Granite boulder approximately 1.80m wide x 3.00m long x 1.00m high with 13 cup-marks at the top. It is located approximately 20m west of Panel VI.

Figure 3.6: Panel II – Photogrammetry of the engraved art processed with Adobe Illustrator CS6

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Leonor Rocha, Paula Morgado 3.5 Conclusion

ends up wearing down or even destroying the existing engravings – a clear example of this can be found on megalithic monuments.

Extensive research undertaken in the Alentejo in the final decades of the 20th and early decades of the 21st centuries, has given rise to important new contributions to the topic of rock art. These have emerged from research focusing directly on this type of evidence, or from the records of projects on similar themes or even as a result of measures taken to minimise impacts on heritage. Generally speaking, with the consolidation of research on this theme we continue to see a clear distinction between engraved and painted art, in terms of both spatial location, and media and motifs. Engraved art also shows a clear distinction with respect to motifs represented and techniques used on panels of granite or schist, with a greater thematic diversity within the schist. One of the simplest explanations for this dichotomy may lie in the ease or difficulty of engraving on either type of rock; making fine strokes, for example, is more difficult on granite, due to its texture.

Two methodologies of study were used during the 20th century. 1) Dichromatic technique, which made it possible to identify engravings using the contrast of black on white. This technique was eventually discontinued because of the possibility of the inks causing rock surface erosion. 2) The direct decal using polyvinyl plastic methodology is still in use today. This limited technique (it cannot be used everywhere) may also destroy the remnants of pigment, when present. For the study of the Penedo do Ferro complex, methodologies primarily based on collecting images (photographs) were chosen as a first approach. The results would determine whether they could later be complemented by occasional direct decals. In none of the panels was damage to the artwork a concern because there were no paintings.

The study, or more specifically, the identification and characterization of both types of media (rock), poses problems. Motifs on granite, as in this particular case, are probably the hardest to recognize due to problems of erosion associated with the rocks in this area, which

The results obtained in this phase only allowed the most significant art to be identified, that is, the art that can be distinguished fairly easily, as one can see from the

Figure 3.7: Panel I after the survey and photogrammetric processing

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The prehistoric open-air sanctuary of Penedo do Ferro

Figure 3.8: Panel I – Photogrammetry of the engraved art processed with Adobe Illustrator CS6

Bibliography

accompanying images. The best results came from Panel I, with a good characterization of the engraved art present on the levelled surface of the floor (Figure 3.7 and 3.8). However, we cannot rule out the possibility that other motifs exist, especially on the walls of Panel I (shelter) but in order to verify this we will need to use night photography with oblique lighting.

Alvim, P. Recintos megalíticos do ocidente do Alentejo Central. Arquitectura e paisagem na transição mesolítico/neolítico. Évora: Universidade de Évora (Tese de mestrado, policopiada), 2009. Alves, L. B. The movement of signs. Post-glacial rock art in north-western Iberia. Reading: Universidade de Reading, Departamento de Arqueologia (Dissertação de doutoramento, policopiada), 2003.

The Penedo do Ferro Sanctuary is of great scientific interest for the study of rock art in this region of the Alentejo. However, as mentioned earlier, due to obstacles that the research team has not yet been able to overcome, the archaeological works have been temporarily suspended.

Baptista, A. M. O Paradigma Perdido. O Vale do Côa e a arte paleolítica de ar livre em Portugal/Paradigma Lost. Côa Valley and the open-air Paleolithic art in Portugal. Porto / Vila Nova de Foz Côa: Edições Afrontamento e Parque Arqueológico do Vale do Côa, 2009.

Acknowledgements To Monforte municipality for financial support to this project and CEAACP the translation. Leonor Rocha – School of Social Sciences - University of Évora; Researcher CEAACP/ FCT/ UALG (UID/ ARQ/ 0281/ 2020). [email protected]; Paula Morgado – Municipality of Monforte; Researcher CHAIA/ FCT/ UÉ [2020] – (UID/ EAT/ 00112/ 2021). [email protected]..

Baptista, A.M. and Martins, M.M. “Gravuras rupestres do Vale do Guadiana: Notícia da sua descoberta”. Informação Arqueológica (1977-1978), I (1979): 17-18. Baptista, A.M and Santos, A. T. “Arte Rupestre do Guadiana Português na área de influência do Alqueva”. Memórias d’Odiana.2ª série, nº 1. EDIA, 2013. 43

Leonor Rocha, Paula Morgado (Évora)”. Actas das V Jornadas Arqueológicas, II. (1993): 93-108. Lisboa: A.A.P.

Breuil, H. “La roche peinte de Valdejunco à la Esperança, prés de Arronches (Portalegre)”. Terra Portuguesa, 1314 (1917): 17-26.

Leisner, G. and Leisner, V. Die Megalithgräber der Iberischen Halbinsel: Der Westen 2. Berlin, 1959

Bueno-Ramírez, P., Balbin Behrmann, R., Rocha, L. and Oliveira, J. “Anthropomorphic image as origins of ancestor´s”Caves”. The stele -menhir of Anta do Telhal, Arraiolos, Évora, Portugal”. In Death as Archaeology of Transition: Thoughts and Materials Papers, edited by L. Rocha, P. Bueno-Ramírez, G. Branco, 83-94. BAR International Series 2708, 2015.

Martins, A. A Pintura Rupestre do Centro de Portugal. Antropização simbólica da paisagem pelas primeiras sociedades agro-pastoris. Faro: Universidade do Algarve (Tese de Doutoramento policopiada), 2014. Oliveira, J. and Borges, S. “Arte Rupestre no Parque Natural da Serra de S. Mamede”. Ibn Maruán, 8, (1998): 193-202. Marvão: C.M.Marvão.

Cerrillo Cuenca, E., Bueno Ramírez, P. and Balbín Behrmann, R. 2019. “3DMeshTracings: A protocol for the digital recording of prehistoric art. Its application at Almendres cromlech (Évora, Portugal)”. Journal of Archaeological Science: Reports, vol. 25 (2019): 171183.

Oliveira, J. and Oliveira, C. “A arte rupestre da Serra de S. Mamede (Portugal – Espanha)”. III Simposium Internacional de Arte Rupestre de Havana (2012): 1836. Havana: Instituto Cubano de Antropología. Rocha, L. “Entre vivos e mortos…arte rupestre e megalitismo funerário na região de Évora. Sinais de Pedra”. I Colóquio Internacional sobre Megalitismo e Arte Rupestre na Europa Atlântica. Évora: Fundação Eugénio d´Almeida, 2004.

Calado, M. “Cromlechs Alentejanos e Arte Megalítica”. Actas do III Colóquio Internacional de Arte Megalítica. 287-297. La Coruña: Museo Arqueolóxico e Histórico, 1997. Calado, M. Menires do Alentejo Central. Génese e evolução da paisagem megalítica regional. Lisboa: FLL. (Tese de Doutoramento policopiada), 2004.

Rocha, L. “Arte rupestre e sociedades camponesas. Uma associação sistemática no Alentejo Central (Portugal)”. In Global Rock Art. Anais do Congresso Internacional de Arte Rupestre. FUMDHA Mentos. IX. Piauí: Fundação Museu do Homem Americano. Artigo 103, 2010.

Calado, M. and Bairinhas, A. “O Santuário Pré-Histórico da Horta da Ribeira (Redondo)”. Actas das V Jornadas Arqueológicas 2, 175-178. Lisboa: Associação dos Arqueólogos Portugueses, 1994.

Rocha, L. “A Arte rupestre de Arraiolos”. Património(s) de Arraiolos (2013): 304-308. Arraiolos: Câmara Municipal de Arraiolos.

Calado, M. and Rocha, R. “Megaliths as Rock Art, in Alentejo (South of Portugal)”. In Proceedings of the XV World Congress UISPP. 7, edited by D. Calado and M. Baldia, 25-31. BAR S2122, 2010.

Rocha, L. ``Nouvelles [et anciennes] données sur l’art mégalithique en Alentejo. ARPI. Arqueología y Prehistoria del Interior Penínsular, 4 (2016): 237-247. UAH: Alcalá de Henares.

Contador de Argote, J., Vieira Lusitano, F. and Rochefort, P. de. Memorias para a historia ecclesiastica do Arcebispado de Braga, primaz das Hispanhas. Tomo II. Lisboa Occidental: Na officina de Joseph Antonio da Sylva, 1734.

Rocha, L. and Morgado, P. Relatório Técnico Científico das Prospecções/2017. PIPA – Levantamento Arqueológico e Arquitetónico de Monforte II – LEVAM II. Acessível nos Arquivos da DGPC, Lisboa, Portugal, 2018.

Correia, V. “Arte Préhistorica. Pinturas rupestres descobertas em Portugal no século XVIII”. Terra Portuguesa. 4, ano I, Maio (1916a): 116-119. Correia, V. “Pinturas Rupestres da Srª. da Esperança (Arronches)”. Terra Portuguesa.5, ano I, Junho (1916 b): 158. Correia, V. El Neolítico de Pavía. Madrid: Comisión de Investigaciones Paleontológicas y Prehistóricas, 1921. Ferraz, A.L. Iconographie des sociétés néolithiques: entre Atlantique et Méditerranée, les stèles décorées de l’Alentejo Central. 2 vols. Paris: École des Hautes Études en Sciences Sociales, 2016. Gomes, M.V. “Arte rupestre e contexto arqueológico”. Almansor, 7 (1989): 225-269. Montemor-o-Novo: CMMN Gomes, M.V., Gomes, R.V. and Santos, M.F. “O santuário exterior do Escoural - Sector SE (Montemor-o-Novo 44

4 Neolithic image, symmetry and context: challenges in montane stone from Cumbria, U.K. Steve Dickinson Abstract The engravings on, and contexts for, a distinctive polissoir located in the course of archaeological survey work at the montane core of the Lake District, Cumbria, U.K., are examined. Conventional understandings of open-air, or landscape, rock art in Britain and Ireland have generally moved away from attempts to interpret it, preferring emphases on its materiality and the processes, performances and cultural transmissions embodied and associated with it. New directions, incorporating digital image interpretation via 1:1 tracing and digital graphical transcription of specific features, for the study of this polissoir and its contexts, emphasises its object-agency at the heart of a mountainous, animate prehistoric landscape associated with largescale stone axe blade production in the Neolithic. Keywords Polissoir – Neolithic – apotropaism – rock art 4.1 Introduction

polissoirs themselves (following Ingold 2011; Malafouris 2013; Olsen 2013). Such accessibility and enaction would encompass the creation of what some prehistorians would term ‘rock art’: ‘human-made marks on natural, nonportable rocky surfaces’ (Thomas 2016, 11, following Taçon and Chippendale 1998, 6).

Polissoirs are well-known from a variety of prehistoric funerary, domestic and landscape contexts across Britain and Europe. In Britain, their characteristics include grooves, polished areas, or both; worked into natural, and sometimes, in the instances of grooves, portable rock surfaces (Darvill 2010, 203-4; Marshall 2016, 52, 69; Thomas 2016, 197). Though patently functional, it can be suggested that they also acted in prehistory as tactile, physical, artefacts that allowed people to access, enact and enable the material qualities, affordances and mutability of stone through the transforming of artefacts, including the

Such transformative processes, from ‘natural’ sources to ‘cultural’ assemblages, have long been suggested in the British Neolithic in the selection of particular stone sources alongside the acquisition, working, distribution and deposition of portable ground and edged stone artefacts in specific locations and contexts (Bradley 2004, Davis and Edmonds 2011, Edmonds 1995, Thomas 2016). A key challenge for archaeologists seeking to interpret British and Irish rock art of this period is that the majority of the open-air art, as encountered in its many landscape settings, is not only difficult to date, but abstract, and thus susceptible to multiple challenges in regard to its interpretation: particularly in the case of cup-and-ring markings, spirals and cupules. Digital technologies, such as Reflectance Transformation Imaging (RTI) (Díaz-Guardamino and Wheatley 2013), photogrammetry and laser scanning help to reveal intricate surface detail, and allow for more accurate assessment of images on rock. New challenges involve the incorporation of these technologies into the montane landscape of the stones; where the application of LiDAR and other digital remote sensing, such as Ground Penetrating Radar (GPR), have specific limitations due to complex geologies and thin stratigraphy. 4.2 Two Upper Eskdale cairns and their contexts In 2015-2017 walkover surveys in the mountains of Upper Eskdale, Cumbria, Britain, revealed sites and artefacts above local cultivation limits in the mediaeval 45

Steve Dickinson and post-mediaeval periods. The first site, Scar Lathing Cairn, is set near the focus of the survey area, a 12 square kilometre natural amphitheatre encircled by mountains and split by a mountain ridge, all above 350 m Ordnance Datum (OD). This cairn features a boulder of banded Borrowdale Volcanic Series (BVS) rock with distinctive natural markings brought out through application of digital photography in low light and RTI. The boulder is positioned on the eastern side of the southern facade of a small low, overgrown, rectangular kerbed cairn (Dickinson and Watson 2016). This cairn, (contra Style 2016), formed an extension to a 14.0m long north-south orientated steep, scree-filled runnel. From the facade the cairn has a distinctive framed view to its north of a prominent adjacent mountain range: from Slight Side (748 m) and Scafell (964 m) to Scafell Pike, (978 m: the highest mountain in England), Broad Crag (931 m), Ill Crag (935 m) and Pen (768 m).

east of the rectangular structure, a huge, stone axe-blade shaped natural boulder protrudes from the turf of this amphitheatre. 4.3 The polissoir, its engravings, grooves and motifs The volcaniclastic sandstone slab (Figure 4.3) features a raised, roughly rectangular concave 510 mm long by 350 mm high, (at the SE), panel with distinctive engravings and grooves, some with bevelled edges, in its surface. The engravings are multi-layered: intersecting, intercutting and superimposed across, on, and with, the grooves (Figure 4.4). The largest groove on the slab is clearly natural in origin, though it shows signs of having been used as a polissoir-groove (see below). Some of the engravings run over the upper edge of the panel and onto the top of the slab, where there is also a cupule. Detailed analysis of the engravings through tracing in situ combined with detailed digital photography demonstrates that they fall into five groups (Figure 4.5):

The second cairn site features a 0.45 m high slab of weathered BVS green-blue volcaniclastic sandstone let into a socket on the edge of a small rectangular structure open to the west, again with a distinctive framed view in this direction of nearby mountains. This structure abuts the north of a natural 17.8 x 9.5 m accumulation of boulders (Esk Pike Ridge/Long Crag Spring Cairn: Figure 4.1 and Figure 4.2): the largest, and most distinctive of which, is a 3.0 m high, 2.5 m wide x 1.3 m thick tabular megalith which displays evidence on its eastern side of having been chocked to the vertical in antiquity. The cairn lies at the SW open end of a large natural amphitheatre. Just to the

1. Highlighted in white: a partial grid of small triangles (Figure 4.3). 2. Highlighted in yellow: four deeper grooves (two of which are vertical) and five horizontal engraved lines, the topmost of which cuts across some of the uppermost triangles. The largest and deepest groove, as noted above is natural in origin and diagonal, running across the panel from its upper right to its lower left. 3. Highlighted in green: Two ‘waisted’ (Davis and Edmonds 2011, 169, citing Fell 1964, 40) Cumbrian-

Figure 4.1: Esk Pike Ridge/Long Crag Spring Cairn, Upper Eskdale, from the south-east (2m scale).

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Neolithic image, symmetry and context type stone axe blade shaped motifs to either side of the deep diagonal groove. 4. Highlighted in pink: two engraved lines that run across the deepest diagonal groove, connecting the base of the right-hand axe blade motif with the bottom of the triangle grid. One of these lines cuts across this motif, linking into five dendritic motifs to its upper right that follow natural slim lines of calcite or quartz naturally embedded in the stone (Figure 4.6). Further engraved lines in the top of this blade-motif give its upper section the appearance of anthropomorphism: as ‘fingers’. On the upper side of the deepest diagonal groove, opposite to where the right-hand axe blade motif meets it, there is a small semicircle carved into the slab. 5. Highlighted in orange: a series of mainly diagonal engraved grooves, giving the appearance of rays engraved/cut from the top right of the slab downwards into its lower right sector. Three of these intercepts the semicircle, and continue across the deep diagonal groove to cut across the right-hand axe blade motif.

Figure 4.2: Plan of the Esk Pike Ridge/Long Crag Spring cairn.

This analysis of the motifs seems to indicate a chronological sequence (from 1 to 5), but it should be noted that the lefthand axe blade motif is more deeply cut into the surface than its twin, and it seems to be respected by the triangle grid: thereby indicating that it may be one of the earliest motifs on the slab.

Figure 4.3: The polissior slab, from the south-east, showing the triangle motifs.

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Steve Dickinson

Figure 4.4: The polissoir slab photographed from the south-east at night, with angled lighting.

Figure 4.5: Engravings, grooves and motifs on the polissoir slab.

48

Neolithic image, symmetry and context and archaeological contexts, enables a focus on its details in relation to its singular location. Its archaeological contexts include: those dated to the Neolithic, when stone axe blades were created in large quantities from specific rock sources in some of the mountains overlooking it (Bradley and Edmonds 1993, Claris and Quartermaine 1989), and those when upland vegetation changed (Pennington 1997). The stone axe blade making sites of the central mountains of the Lake District were the largest in Britain. Blades from the area circulated across most of Britain and Ireland. The polissoir’s contexts also include assessing the issues and challenges surrounding the ascription and identification of ‘Atlantic’ rock art, (Bradley 1997) described as a prehistoric rock-carving practice found from Portugal across Spain, France, Ireland, England and Scotland (Valdez-Tullett 2019, 1). The motifs created by this practice range from cup marks and cup-and-ring markings through spirals, zoomorphs, anthropomorphs, weapons and figurative examples (Valdez-Tullett 2019, 3–6). With a common range of such designs and techniques of making, the repertoire of this is commonly split into open-air rock art and megalithic or passage-grave art, the latter set in ‘architectural’ rather than ‘landscape’ locations (Thomas 2016, 11). As noted above, the majority of British and Irish landscape rock art is not only hard to date, but, being abstract, is capable of bearing multiple interpretations in respect of the intentions of its makers. As has been noted by Richard Bradley, ‘rock art research must contribute directly to archaeology if it is to achieve anything of value’ (Bradley 1997, 8). As an addition to this, we may also note that, following Antonia Thomas (2016, 11), and others, it is all too easy to ascribe and apply modern assumptions and values to this ‘art’, which may be totally unrelated to the practices and the values of the peoples who created it in the past. Such values in prehistory in this Upper Eskdale montane environment arguably involved a perceived animacy in specific contexts of stone, and people acting in reciprocity with specific stone sources and their host mountains as a form of apotropaism (Dickinson 2019, 175).

Figure 4.6: Detail of the semi-circle and the top of the anthropomorphic axe-hand on the polissoir, above, and above left, of the centimetric scale. A group of the dendritic/‘ramiform’ motifs are at top left.

The deepest horizontal grooves (2), on the left of the slab have bevelled edges, as does the top right element of the distinctive deep diagonal groove. These are the elements on the slab that indicate the clearest use of it as a polissoir. The walkover surveys, and associated geological consultations, have strongly indicated that this slab’s focused markings and deliberate setting are not paralleled by others yet identified in the survey area, or by the natural glacial and post-glacial markings and processes visible on the surface geologies of the area. Archaeological assessment with the benefit of digital imaging also includes comparing the Upper Eskdale polissoir engravings to those from other sites. The Upper Eskdale triangular motifs can be found in profusion at the Ness of Brodgar (Thomas 2016), and in the passage tombs of Newgrange (O’Kelly 1984, for example on R18: 174, and on K91: 165) and Knowth (Eogan 1986, for example, on Or. 45, and on Or. 54: 188). The dendritic motifs on it find parallels in the so-called ‘ramiform’ motifs noted by Robin on stones at Newgrange, Knowth and Loughcrew, and also in Brittany at Guib, Table des Marchands and Lannec er Gadouer (Robin 2012, 144–145). The small axe blade motifs are paralleled by a divided, waisted central motif on one of the small Neolithic chalk plaques found in a pit on the King Barrow ridge near Stonehenge (Harding 1988, 320–327). The semicircle abutting a groove opposite a complex axe-anthropomorphic motif is a singular double-motif not paralleled elsewhere: this conjunction is further discussed below.

The Upper Eskdale slab engravings find some of their closest comparisons not in the open-air art of the majority of Atlantic rock art contexts, but, as has been noted above, in the confined spaces of megalithic tombs, and in architectural ‘domestic’ and ‘ritual’ situations, as excavated and recorded, for example, on Orkney (Card and Thomas 2012, Thomas 2016). However, there is another, much larger, montane rock art group which can be paralleled with them on the boulders at Copt Howe in Great Langdale, just over 8 km to the east of the Upper Eskdale slab (Bradley et al. 2019, 177–192, Figure 4.7). At the principal Copt Howe boulder featuring art, the largest motif group, as on the Upper Eskdale slab, is also split by a prominent natural groove running from the right to the left of the rock, and, again as on the Upper Eskdale slab, there is another nearly vertical groove that bisects this group. The Copt Howe site is located just over 3 km from the Langdale Pikes. To its west lie sources of the majority

4.4 Contexts for the polissoir This polissoir, positioned in its geological (Millward et al. 2000, 33–40, 105, 110), geomorphological (Wilson 2010), 49

Steve Dickinson

Figure 4.7: Copt Howe, Great Langdale, Cumbria: the motif group and natural grooves and features on the principal boulder (scale at left is in 0.50 m bars).

of the Neolithic stone axe blades from the Lake District. Some of the motifs on the boulders here have been linked to similar motifs in Irish passage grave art (Bradley et al. 2019, 187). The two principal boulders at this site form a natural gateway that allows clear sight of the sun when it passes behind Harrison Stickle (736 m), one of the most prominent of the Langdale Pikes), as it sets in midsummer (Sharpe 2007, 167–169; Sharpe and Watson 2013).

It is possible (contra. Cochrane and Meirion Jones 2012, 2, 4) within those apotropaic, animistic and mountain horizon/ celestial event parameters that the semi-circle and its associated anthropomorphic axe-motif on the Upper Eskdale slab can be interpreted, as can the uses, affordances and positioning of the slab upon which they appear in relation to the cosmology of the area. The semi-circle conceivably represents a celestial object being drawn down across a rift (the natural diagonal groove) by the anthropomorphic axehand below it. The rift, in the world of Upper Eskdale, is the huge valley of the River Esk which lies due west of the slab and its cairn, a valley which separates the slab and cairn from the high mountains to the north-west. This event is most striking in mid-summer, when the setting sun, (as seen by an observer standing at the site in clear weather) disappears behind the Scafell-Scafell Pike massif to the north-west.

A similar celestial phenomenon to that which occurs in Great Langdale is provided, with demonstrable substantial enhancements in both the summer and the winter, at the Upper Eskdale Long Crag Spring Cairn slab site when one stands up from it and looks to the Scafell massif to the north-west and the west. Here, the winter and summer solstice sun settings can be both observed and measured using the mountain peaks as horizon indicators, and a similar set of celestial calendrical observations can be made with major lunar setting standstills. Looking east, an intervening ridge running south from the summit of Esk Pike (885 m), blocks a view of most of the mountain peaks from Bowfell (902 m) to Crinkle Crags (859 m) and Little Stand (727 m). However, Neolithic cairns and sites further up this ridge have clear views of these mountains from the north-east round to the south-east, the directions of summer and winter solstice sunrises and northern to southern major lunar standstills (Figure 4.8). The ridge itself, with its many spectacular natural rock formations and platforms, would have provided not only an access route up on to the mountains that encircle it, but also opportunities for veneration and acts of apotropaism at the time of prehistoric stone sourcing. Apotropaism and mountains have a long history in many contexts (Dora 2016).

The discovery in prehistory of cosmological ordering of certain landscapes in relation to rock art has also been noted by researchers in other contexts for example, in the Kilmartin area of Argyllshire (Jones 2011, Jones and Watson 2011). The gateway between the two largest Copt Howe boulders, allowing access to the inner recesses of the Great Langdale valley, its montane stone sources and celestial midsummer event is matched by the gateway of the Esk Pike Ridge/Long Crag Spring Cairn in relation to Esk Pike, access to similar, remoter stone sources, and to the celestial events visible from sites on this ridge. 4.5 Object-agency, symmetry, transformation, apotropaism It is thus suggested that this polissoir embodied both an object-agency, (Gell 1998, 17–21, Nyland 2020) and 50

Neolithic image, symmetry and context

Figure 4.8: A SE-N-SW 240º panorama of Upper Eskdale’s summits around the rock platform of Low Gait Crags on the Esk Pike ridge.

potency that acted symmetrically in prehistory in artefacts that were transformed on it in its specific montane and celestial contexts, and through the image-making and markings on, and incorporating, the material of the polissoir. Acts of sourcing and transforming montane stone through the art on this slab, and axe blade creation, did not occur in isolation, but were arguably part of a larger set of landscape, celestial and ritual or mythological contexts (Taçon 1991). These found expression in deliberate acts of human and material transformation of, and on, the rock of the Upper Eskdale polissoir itself. The polissoir can be seen as representing key mountains from its south-west to north-west including their high, remote sources of stone used to manufacture axes, the celestial activities above them, and acts of apotropaism in regard to both.

Bradley, R., Watson, A. and Style, P. “After the Axes? The Rock Art at Copt Howe, North-west England, and the Neolithic Sequence at Great Langdale”. Proceedings of the Prehistoric Society 85 (2019): 177–192. Card, N. and Thomas, A. “Painting a picture of Neolithic Orkney: decorated stonework from the Ness of Brodgar.” In Visualising the Neolithic: Abstraction, Figuration, Performance, Representation Neolithic Studies Group Seminar Papers 13, edited by A. Cochrane and A. Meirion Jones, 111–124.Oxford: Oxbow Books, 2012. Claris, P. and Quartermaine, J. “The Neolithic Quarries and Axe Factory Sites of Great Langdale and Scafell Pike: A New Field Survey”. Proceedings of the Prehistoric Society 55 (1989): 1–25.

Acknowledgements

Cochrane, A. and Meirion Jones, A. “Visualising the Neolithic: an introduction.” In Visualising the Neolithic: Abstraction, Figuration, Performance, Representation Neolithic Studies Group Seminar Papers 13, edited by A. Cochrane and A. Meirion Jones, 1–14. Oxford: Oxbow Books, 2012.

Thanks to Aaron Watson for his invaluable advice and RTI, photogrammetry work; to geomorphologist Peter Wilson and geologists Alan Smith and Hugh Tuffen for their advice on surface features of the Borrowdale Volcanic Series; to Richard Bradley, to Marisa Giorgi, to Nathalie Brusgaard, Manuel Santos-Estévez, Ana Bettencourt and Julian Jansen van Rensburg. Thanks also for the comments and suggestions from participants and attendees at sessions incorporating presentations of aspects of this research at the 4th International Landscape Archaeology Conference, Uppsala 2016, at the Images in Stone in Prehistory and Protohistory Symposium, University of Minho, Braga 2016, at the Theoretical Archaeology Group Conference, University of Southampton 2016, at the Neolithic Studies Group Seminar at the British Museum 2017, and at the IFRAO Rock Art Congress, 2018, Valcamonica.

Darvill, T. Long Barrows of the Cotswolds and Surrounding Areas. Stroud: The History Press, 2010. Davis, V. and Edmonds, M. (eds). Stone Axe Studies III. Oxford: Oxbow Books, 2011. Díaz-Guardamino, M. and Wheatley, D. “Rock Art and Digital Technologies: the Application of Reflectance Transformation Imaging (RTI) and 3D Laser Scanning to the Study of Late Bronze Age Iberian Stelae”. Menga 04: Journal of Andalusian Prehistory 3,04 (2013): 187–203. Dickinson, S. and Watson, A. “Patterns on the rock: an unusual cairn in the Lake District, Cumbria”. PAST: The Newsletter of the Prehistoric Society 83 (2016): 13–14.

Bibliography Bradley, R. Rock Art and the Prehistory of Atlantic Europe: Signing the Land. London: Routledge, 1997. Bradley, R. An Archaeology of Natural Places. London: Routledge, 2004.

Dickinson, S. ``Moving Mountains: Reciprocating with rock in the Neolithic’’ In Mining and Quarrying in Neolithic Europe: A Social Perspective. Neolithic Studies Group Seminar Papers 16, edited by A. Teather, P. Topping and J. Baczkowski, 163–178. Oxford: Oxbow Books, 2019.

Bradley, R. and Edmonds, M. Interpreting the axe trade: Production and exchange in Neolithic Britain. Cambridge: Cambridge University Press: New Studies in Archaeology, 1993. 51

Steve Dickinson Pennington, W. “Vegetational history.” In A Flora of Cumbria edited by G. Halliday, 42–50. Lancaster: University of Lancaster, 1997.

Dora, V. D. Mountain: Nature and Culture. London: Reaktion Books, 2016. Edmonds, M. Stone Tools and Society: Working Stone in Neolithic and Bronze Age Britain. London: B.T. Batsford, 1995.

Robin, G. “The figurative part of an abstract Neolithic iconography: hypotheses and directions of research in Irish and British passage tomb art.” In Visualising the Neolithic: Abstraction, Figuration, Performance, Representation, edited by A. Cochrane and A. Meirion Jones, 140–160. Neolithic Studies Group Seminar Papers 13. Oxford: Oxbow Books, 2012.

Eogan, G. Knowth and the passage-tombs of Ireland. London: Thames and Hudson, 1986. Fell, C. “The Cumbrian type of polished stone axe and its distribution in Britain”. Proceedings of the Prehistoric Society 30 (1964): 39–55.

Sharpe, K. E. “Rock-art and rough-outs: exploring the sacred and social dimensions of prehistoric carvings at Copt Howe, Cumbria.” In Art as Metaphor: The Prehistoric Rock-Art of Britain, edited by A. Mazel, G. Nash and C. Waddington, 151–173. Oxford: Archaeopress, 2007.

Gell, A. Art and Agency: An anthropological theory. Oxford: Clarendon Press, 1998. Harding, P. “The chalk plaque pit, Amesbury”. Proceedings of the Prehistoric Society 54 (1988): 320–327. Ingold, T. Being Alive: Essays on movement, knowledge and description. London: Routledge, 2011.

Sharpe, K. E. and Watson, A. “Moving images: interpreting the Copt Howe petroglyphs.” In Carving a Future for British Rock Art: New directions for research, management and presentation, edited by T. Barnatt and K. Sharpe, 57–64. Oxford: Oxbow Books, 2013.

Jones, A. “Coda: Animating Landscapes.” In An Animate Landscape; Rock Art and the Prehistory of Kilmartin, Argyll, Scotland edited by A. Meirion Jones, D. Freedman, B. O’Connor, H. Lamdin-Whymark, R. Tipping and A. Watson, 324–333. Oxford: Windgather Press, 2011.

Style, P. “Ring cairns and their variants from the Cumbrian Mountains: A response to Steve Dickinson and Aaron Watson: Patterns on the rock: an unusual cairn in the Lake District, Cumbria (PAST 83)”. PAST: The Newsletter of the Prehistoric Society 84 (2016): 8–9.

Jones. A. and Watson, A. “An Animate Landscape II: the sacred geography of prehistoric Kilmartin.” In An Animate Landscape; Rock Art and the Prehistory of Kilmartin, Argyll, Scotland, edited by A. Meirion Jones, D. Freedman, B. O’Connor, H. Lamdin-Whymark, R. Tipping and A. Watson, 270–281. Oxford: Windgather Press, 2011.

Taçon, P. S. C. “The power of stone: symbolic aspects of stone use and tool development in western Arnhem Land, Australia”. Antiquity 65 (1991): 192–207. Taçon, P., and Chippendale, C. “An archaeology of rockart through informed methods and formal methods.” In The Archaeology of Rock-Art, edited by C. Chippendale and P. S. C. Taçon, 1–10. Cambridge: Cambridge University Press, 1998.

Malafouris, L. How Things Shape the Mind: A Theory of Material Engagement. Cambridge, Massachusetts and London: The MIT Press, 2013. Marshall, S. Exploring Avebury: The Essential Guide. Stroud: The History Press, 2016.

Thomas, A. Art and Architecture in Neolithic Orkney: Process, Temporality and Context. University of the Highlands and Islands Archaeology Institute Research Series 1. Oxford: Archaeopress, 2016.

Millward, D., Johnson, E. W., Beddoe-Stephens, B., Young, B., Kneller, B. C., Lee, M. K., Fortey, N. J., Allen, P.M., Branney, M. J., Cooper, D.C., Hirons, S., Kokelaar, B. P., Marks, R. J., McConnell, B. J., Merritt, J. W., Molyneux, S. G., Petterson, M. G., Roberts, B., Rundle, C. C., Rushton, A. W. A., Scott, R. W., Soper N. J. and Stone, P. “Geology of the Ambleside district”. Memoir of the British Geological Society, Sheet 38 (England and Wales). London: The Stationery Office, 2000.

Valdez-Tullett, J. Design and Connectivity: The Case of Atlantic Rock Art. Archaeology of Prehistoric Art, Vol. 1(BAR International Series 2932). Oxford: BAR Publishing, 2019. Wilson, P. Lake District Mountain Landforms. Lancaster: Scotforth Books, 2010.

Nyland, A. J. “In Search of Cloudstones? The Contribution of Charismatic Rocks Towards an Understanding of Mesolithic and Neolithic Communities in the Montane Regions of South Norway”. Proceedings of the Prehistoric Society 86 (2020): 43–64. O’Kelly, M. J. Newgrange: Archaeology, art and legend. London: Thames and Hudson, 1984. Olsen, B. In Defence of Things: Archaeology and the Ontology of Objects. Altamira Press, 2013. 52

5 New technologies for the survey, documentation and representation of rock art remains Gianni Furiassi Abstract This work illustrates the survey and data acquisition methods of three case studies: Anfratto Palmerini (Monte la Queglia, Pescara, Italy), Parete Manzi (Montelapiano, Chieti, Italy), Pietra delle Croci (Lettopalena, Chieti, Italy). The acquisition of data and their threedimensional digital representation is a dissemination tool that allows one to reach an everwidening audience. Identifying the most appropriate data acquisition and restitution methodology and the variables that affect them is a priority in the documentation phase. Only in this way can we overcome the geographical distances and the difficulties of accessing and using rock art sites. The documentation can be enriched with real time updated information and new comparisons. The cognitive experience and the touristic-cultural use assume dynamic and constantly evolving aspects. Conservation, remote multidisciplinary study and conservative / museum design are the future objectives to which the new technologies in the field of rock art are aimed. Keywords Virtual reality – 3D modelling – laser scanners – archaeology – rock art 5.1 Introduction

range of technological solutions is a factor that should not be underestimated. In some cases, it can lead us to inappropriate choices, in terms of results, costs and usability. Accordingly, the need to gather data and draw considerations that in the future can guide conscientious operational choices. The difficulty in making a choice regarding the best technology to use, respectively the three technical aspects mentioned, comes from the need to analyse multiple variables that are difficult to interpret, yet can provide the expected results if properly evaluated.

The 20th International rock art Congress IFRAO, held in Darfo Boario, was an opportunity to reflect on the topics related to technical aspects, until now overshadowed by discoveries and pure archaeological data. The three technical aspects to take into consideration when we talk about “new technologies” applied to archaeological research, especially in the rock art field are: data acquisition systems, representation methods, the accessibility criteria of data and use. The possibility of accessing a wide

The three sites illustrated as examples, are: “Parete Manzi – Montelapiano (CH) Italy”, “Anfratto Palmerini – Pescosansonesco (PE) Italy”, “Pietra delle Croci – Lettopalena (CH) Italy”. During the survey and graphic restitution works, the three technical aspects mentioned were studying, analysing and comparing parameters such as difficulties of site access, dimensions and visibility of the figures represented, morphology of the illustrated support, dimensions, light conditions, possibility of long-term conservation, site usability, etc. The evaluation of the above parameters plays a key role in choosing the survey technique to be used and the type of graphic illustration, not just for documentary purposes but also for the use and dissemination of the site. In three different sites, surveys were carried out with three different methodologies. This allowed us to represent the archaeological data with different graphic representation methods, compare limits and advantages of the various survey methods, and evaluate the strengths of different graphic representation systems of data. 53

Gianni Furiassi 5.2 Survey

overlap on the four sides of each photograph (Gopi 2006, 259) and that each image has been made at the same distance from the object. These basic requirements are essential for the software to process images without producing errors in 3D geometry.

5.2.1 The choice of the method and technology used in the data acquisition phase The data acquisition phase raises the issue of which methodology to be used. The variables to consider are various: accessibility of the site, type of surface to be surveyed, how the figures were produced (engraving, painting, etc.), lighting conditions, weather conditions.

With regards to the instrumentation used in the photographic acquisition phase. During the 3D photogrammetric survey, a Phantom 3 Professional drone was used to allow a very accurate processing of the 3D model. 5.2.4 Laser Scanner Survey

Taking into consideration the above-mentioned variables, we identified the survey method which best suited the site under examination.

Advantages: millimetric precision, measurement is not subject to particular lighting conditions (unless you are working on a reflective surface); no dimension limit for the surface to scan.

5.2.2 Manual Survey Advantages: ease of transport, low-cost, and no specific skills are required. Limits: Poor detection accuracy, limited detectable dimensions, not all surfaces are suitable for this methodology, and the generation of new errors in post-production when digitising the data.

Limits: difficulty to transport and installing equipment, specific technical skills are required (both for acquisition and for graphics rendering). In this specific case a scanner with an acquisition system called “time of flight”, produced in Germany by Dr. Clauss Bild- und Datentechnik GmbH, model RODEO smartscan, was used. The point cloud acquisition configuration used is shown in table 5.1.

The manual or contact survey illustrates, with greater precision, the paintings and the engravings points in the various chronological overlaps, allowing us to give an analytical account of the situation. Compared to photography and pictorial reproductions, which can alter the original sense, this technique returns a faithful and lifesize example of the entire illustrated panel (Zambianchi 2008, 60). The contact survey is an excellent rapid intervention system, which at the objective acquisition of figurative data combines the ease of transport and the low cost of the equipment used, namely: transparent sheet, indelible markers and adhesive tape. The main limitations of this methodology emerge in the data digitization phase, because the dimensions of the support on which the figures were detected do not always allow scanning, and if composed of several separate sheets, it isn’t always easy to merge again without incurring gross errors. A series of methodological measures to be carried out in the survey phase are not always compatible with the need to survey a rock art site (Barberini 2006, 44).

The high-resolution panoramic photo acquisition was carried out with a Nikon 3200 reflex camera and a Samyang Fish-Eye CS II lens mounted on a Pixplorer panoramic head by Dr. Clauss Bild. The raw photos were taken with the parameters f / 3.5 1 / 250s ISO100 8.00mm, and were 6016 x 4000 pixels in size. Panoramic photos were taken and superimposed on the cloud of points to increase the relief detail until obtaining a photographic quality cloud, capable of returning the exact measurements of each engraving, with a close to millimetric precision. The 3D model processing made it possible to create an accurate two-dimensional vector representation and a high-resolution ortho photogrammetric image.

5.2.3 3D photogrammetric survey

5.3 Parete Manzi – Montelapiano (Ch) Italy

Advantages: ease of transport, low cost of equipment (camera, tripod, software), not affected by particular conditions of the surface, applicable to almost all contexts where the light conditions allow, large detectable dimensions. Limits: not extremely precise measurement, consistent and errors (distortions) can be generated.

A series of rock carvings, impressed on the rocky ridge between the municipalities of Montelapiano and Villa Santa Maria (province of Chieti), were discovered by Prof. Aurelio Manzi in 20101. The representations, falling within the municipality of Montelapiano, are located at 445 meters above sea level, on the west side of the ridge (Di Fraia 2012, 1).

The greatest obstacle is obtaining a good uniformity exposure, which can often be extremely difficult in certain contexts. It is therefore important to plan the photographic acquisition campaign based on solar exposure, times and weather conditions. Another fundamental aspect is to make sure that the entire geometric surface to be detected has been photographically acquired, with at least a 25%

The representations are located on a portion of a vertical wall approximately 90 cm in height and 300 cm in width.  http://www.fastionline.org/micro_view.php?itemkey=fst _ cd&fst_ cd=AIAC_3762 1

54

New technologies for the survey, documentation and representation of rock art remains Table 5.1 Points (in millions)

Range or. (degrees)

Resolution or. (degrees)

Range ver. (degrees)

Resolution ver. (degrees)

Scan time

4

360

0,120

165

0,125

10

The repertoire is entirely engraved, except from a single painted black figure. The only mobile artifact found is a trapezoidal section of a flint blade median fragment, found in the lower part of the ridge. The figures, well preserved (except some executed with more subtle strokes), are in some cases covered by a limestone veil that does not compromise their legibility. They are juxtaposed and, in some cases, overlapping, with different patinas and traits, therefore probably engraved at different times. Strong stylistic and dimensional coherence suggests cultural homogeneity and probable chronological continuity (Di Fraia 2012, 3-5). The main figurative motifs relate to fishing: fish and harpoons figures are the most common panel elements. Other elements represented include stars, leaves (one of these ends with a small rhomboid shape that could schematically represent an anthropomorph), a butterfly, a group of lozenges, pectin and stair-forms, groups of lines and squares, and a Solomon’s knot. The representation of fish is certainly one of the most interesting aspects. The typology is articulated and includes at least 10 certain specimens, doubts remain about other 4 or 5 illustrations. The most singular figure is a cetacean, possibly a whale.

ortho-photogrammetric image. It is possible to draw the vector directly on the two-dimensional panoramic image acquired on the same points cloud station associated with it.2 These two examples of data representation are the basis of the documentation produced for a virtual reality visualisation system. It was therefore possible to create a 3D model in 1:1 scale in virtual reality and textured with photographic quality. The mesh obtained from the point cloud was texturized with a high-resolution photoplan using the Blender 3d modelling software.3 The resulting product, including textures and lights, was imported into an integrated multi-platform authoring tool called Unity, which allowed the creation of virtual reality navigation tools, measurement and superimposition of textures bearing digitised rock engravings.4 The final product allows for the possibility of virtually positioning yourself in front of the wall and viewing the rock engravings, making measurements and viewing the texture of the highlighted digitised engravings (Figure 5.2). 5.4 Anfratto Palmerini – Pescosansonesco (Pe) Italy

5.3.1 The Parete Manzi Relief

The Anfratto Palmerini (Palmerini Ravine) was discovered in 2016 in occasion of explorations aimed at reconstructing the oldest settlement processes in the Casauriense area by the archaeologist Guido Palmerini, from which it takes its name (Palmerini and Furiassi 2017, 48-50). The ravine paintings are in red ochre and there are several filiform and possible anthropomorphic engravings. In the immediate vicinity of the site several fragments of impasto pottery were found scattered on the surface including one with an impressed cord attributable to the Bronze Age. Following the discovery of this site a manual contact relief was made and the site was reported to the local Superintendence for Archaeological Heritage.5 The ravine, located in the municipality of Pescosansonesco (PE - Italy) at an altitude of 560 metres above sea level, looks like a narrow-truncated cone cavity degrading inwards, for about 2 m depth and in height between 120 cm in the external part and 40 cm in the innermost. Access and manual survey of the rock art, concentrated on the north wall of the ravine, is made difficult by the conformity of the ravine, the narrow space, and the curvature of the surface of the rock art panel. The evident state of degradation and the difficulties related to visibility and manual approach, made it necessary to carry out an instrumental survey and documentation (Figure 5.3).

The prohibitive access at the point where the Parete Manzi engravings are present, requires digital documentation containing the greatest amount of information. The possibility of acquiring high-resolution geometries and images of an engraved wall that is difficult to access, is certainly a scenario that calls for the production of faithful and definitive documentation. This allows for an archaeological context to be established and becomes an opportunity to deepen the study and research of the representations over time. To remedy visibility problems, due to the colour and size of the engravings with respect to the entire figurative panel, high-resolution panoramic photos, subsequently superimposed on the points cloud were undertaken so as to appreciate the detail of all the engravings without distortion (Di Fraia et al. 2017, 45). To acquire all the geometries of the wall and obtain point clouds that would contain all the geometric data useful for the rock representations two scans were made. Panoramic photos were taken on the same station points and superimposed on the cloud of points to increase the detail of the survey and obtain a photographic quality cloud point, from which it would be possible to return the exact measurements of each engraving with millimetric precision (Di Fraia et al. 2017, 46) (Figure 5.1).

 www.lupos3d.com  www.blender.org 4  unity3d.com 5   Soprintendenza Archeologia Belle Arti e Paesaggio dell’Abruzzo. 2

The processing of the 3D model with the LupoScan software has enabled us to create an accurate two-dimensional vector representation and a high-resolution two-dimensional

3

55

Gianni Furiassi

Figure 5.1: Laser scanner survey digitization with LupoScan software.

Figure 5.2: Virtual reality representation of the “Parete Manzi”.

From the reliefs obtained it was possible to divide the rock art into three different types: a small collection of red ochre figures, a series of rock engravings to overwrite the red figures (blue lines in the image 3 and 4) and the remains of some black pictograms, almost completely faded, made in charcoal. The paintings are concentrated in a single point and consist of a series of positive right handprints with five fingers complete, topped by a floral pictogram (Palmerini

and Furiassi 2017, 48-49). Among the engravings, it was possible to distinguish four different types of rock art: horizontal lines, stair-forms, anthropomorphic, stylized vulva. The methodology used for the instrumental survey and the graphic rendering is the same used in the parete Manzi. The difference was the need for complete data to be presented 56

New technologies for the survey, documentation and representation of rock art remains during the discovery communication phase and technical documentation. This was expressed through an objective vector representation of the paintings and rock engravings and a scale photo-plan, in addition to the cave 3D model and its representation in a virtual environment. In this specific case it was created in natural size (Barberini 2006, 43-44) (Figure 5.4). The conditions were eminently suitable for the laser survey and allowed us to create a complete technical documentation that respects both the criteria of measurability and iconographic reading of paintings and engravings. The strong point is undoubtedly the creation of the straightened photoplan. Using the point cloud as a basis for the creation of a true to life sized high-quality photo perfectly projected. This provides a technical reading tool and allows us to appreciate the figures in a realistic way. If we compare the digitization extrapolated from the figure’s laser relief present on the ravine wall with the contact survey digitised, we can appreciate the manual detection error level, given by the distortion of the sheet that occurred in tracing the figures (Figure 5.5). The projection of the images resulting from the laser scan returns the exact distance between the figures. The comparison between technical data and manual data provides a complete picture of the distribution of the illustrated panel.

Figure 5.3: Technical documentation of the “Anfratto Palmerini” rock figures.

Figure 5.4: Digitization detail of the “Anfratto Palmerini” rock figures

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Gianni Furiassi

Figure 5.5: Comparison of the Manual and the instrumental survey of “Anfratto Palmerini”.

5.5 Pietra Della Croci – Lettopalena (Ch) Italy

This solution showed substantial limits, not much in the laser acquisition, but in taking the photograph due to the tendentially vertical position of the camera. The engravings were photographed at the limits of the lens, with the greatest degree of distortion possible. This has caused the presence of chromatic aberrations and a resolving yield that has lost its effectiveness in the rectification phase. The best data remains the rock morphological information. Subsequently a direct survey (with transparent paper) and a photogrammetric drone survey were made. At this point all the information for a realistic stone 3D reconstruction and technical documentation was gathered. The laser scanning, even without accurate photographic data, allowed us to scale the 3D model generated by the photographs. An acceptable photographic resolution model that combined with manual relief provides accurate and faithful documentation. The boulder size and the context in which it is inserted should be considered important. The rich vegetation does not allow one to approach easily, and its dimensions do not allow a reading of the engravings, placed on its horizontal surface, without climbing the boulder. These particular conditions, besides hindering the activities of an instrumental survey, also limit the simple visual recognition of the engraved images, preventing their study and tourist use (Amoretti and Varani 2016, 6673). In order to allow the reading and usage of the Stone of Crosses engravings, it was therefore decided to digitise the entire figurative repertoire in CAD using the texture

The Pietra delle Croci (Stone of Crosses) of Lettopalena (CH) was presented for the first time at the 20th International rock art Congress IFRAO. It is a large boulder located in an area crossed by ancient sheep tracks. The boulder is dome-shaped, inclined towards the west and largely covered with engraved figures with wide and deep grooves. The most frequently recorded symbols are crosses, simple or enhanced, with a crossbar at the end of the arms, probably Christian. The latter type is most numerous and can be attributed to the modern age. However, other figures seem prehistoric, most notably the rhombus shapes and cross engraved on circles, an eight spoked wheel and a pair of horns. There are also several cupules, of various diameters. The largest is connected by a groove to two small cupules, placed a little higher. Other cupules are also connected by grooves. Finally, there are some cylindrical holes, a few centimetres wide and deep. All these cavities raise many interpretative issues that will require further research (Ciabarra et al. 2018, 498) (Figure 5.6). The large dimensions of the Pietra delle Croci have made the survey operations difficult. The laser scanning was carried out by positioning the instrument directly on the boulder surface, as dense vegetation and the large size of the stone did not allow it to be undertaken from a distance. 58

New technologies for the survey, documentation and representation of rock art remains

Figure 5.6: “Pietra delle Croci” Aerial photo. The stone is surrounded by vegetation.

extrapolated from the aerial photogrammetric relief, corrected through a straightened photo of the manual relief, creating an augmented reality display system as a final product. The figurative digitization took place by straightening a contact relief orthogonal photo and importing it into the CAD environment (Barberini 2006, 48-51). Superimposing the images of the texture on the manual relief, made it possible to grasp the photographic image details and have a more accurate relief (Figure 5.7).

digitization software such as LupoScan, as the extrapolated point cloud does not always allow it. However, the cloud can be used to create a photoplan that serves as a basis for vectorization in CAD.6 The realisation of the contact relief, in the Pietra delle Croci site case, proved to be a particularly useful tool, as it made it possible to relocate the photographic texture images, obtained from the aerial photogrammetric survey, on a plane, and therefore create easily readable documentation that can be used for multimedia processing. The three sites mentioned which have different stylistic, morphological and logistic characters, represent a valid example for the different methodologies definition to be used in the acquisition process and representation archaeological data. It was possible to identify standardised acquisition geometries methods and to identify the data digital representation potential, especially considering the multiple usability requirements. The 3D survey plays a decisive role for accurate scientific documentation and for the development of graphic representations intended for different levels of users. The acquisition and digitization procedures were therefore oriented to the production of technical archaeological documentation, but also to possible

5.6 Data Representation The experiments carried out so far in the digitization of rock art sites context have clarified some aspects mainly related to 3D survey techniques. In classical archaeological contexts the use of a laser scanner survey is an established and undisputed method in recording the presence of structures, ruins or excavation trenches. We now see how in particular geographic and morphological contexts, prehistoric art shows us some interesting examples, which may make the laser scanner survey difficult (Campana and Francovich 2006, 333). If we consider that the digitization and graphical representation data phase of the 3D model in rock art sites always requires the figurative apparatus vectorization, when using the photogrammetry, we are forced to find alternative solutions to the use of direct

 www.lupos3d.com

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Gianni Furiassi

Figure 5.7: The “Pietra delle Croci” three-dimensional reconstruction by photogrammetry.

developments in the field of tourism, teaching, e-learning and shared knowledge.7 The aim is to increase the intrinsic value of this documentary heritage, linked to the possibility of being exploited in different fields (Arrighetti et al. 2013, 31-32) (Figure 5.8). The different data acquisition and graphic representation methods, combined according to the practical needs that we encountered in different contexts, allowed us to always obtain complete technical documentation. The graphic representation facilitates the learning and knowledge of a site, especially if used by a specialised and capable user. Archaeology has become a multidisciplinary activity that is aimed at an increasing number of users: museum operators, tourism and cinema operators, historians, philosophers, architects, enthusiasts, educators. However, archaeological graphical representation, without the possibility of being able to be clearly displayed will always remain relegated to an elitist and professional world.

 For an in-depth analysis on e-learning state in Italy expressed at university level, the contribution of Cantoni and Esposito from 2004 available at the link is interesting: http://www.chersi.it/listing/ dol_06_07/2_02_07_nt_did/second_sett/materiali/newmine_cantoni_ alii_ctu.pdf. 7

Figure 5.8: Example of rock engravings visualization with augmented reality

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New technologies for the survey, documentation and representation of rock art remains Laser scanning surveys and 3D modelling today contribute to the graphic representation needs that are expressed with greatest potential in virtual and augmented reality. The possibility of viewing “as in reality” an otherwise inaccessible and destined to deteriorate site, is the best possible solution. When the realisation of technical drawings fails to express the archaeological site features, and its scientific interpretation, can falsify or alter some characteristic aspects, synthesising contexts too much. The technical documentation, drawn up to widely approved standards, remains a confidential reading, accessible only to those who have the same technical knowledge. Consequently, it becomes necessary to use a language accessible to all, that always takes into account training and educational aspects. The latest information technologies offer a great opportunity for the growth of the archaeological discipline, but only analysing the opportunities and starting a data standardisation and language uniformity work.

Di Fraia, T., Furiassi, G., Palmerini, G. and Ciabarra, C. “Parete Manzi (Montelapiano, CH)”. In Notiziario di Preistoria e Protostoria – 2017, 4.II, Neolitico ed età dei Metalli. Italia settentrionale e peninsulare, edited by M. Miari and F.R. Borel, 45-47. Firenze: IIPP, 2017. Gopi, T. Advanced Surveying: Total Station, GIS and Remote Sensing, Dorling Kindersley (India), 2006. Palmerini, G. and Furiassi, G. “Anfratto Palmerini (Pescosansonesco, PE)”. In Notiziario di Preistoria e Protostoria – 2017, 4.II, Neolitico ed età dei Metalli. Italia settentrionale e peninsulare, edited by M. Miari and F.R. Borel, 48-50. Firenze: IIPP, 2017. Zambianchi, C. ““Quasi una vacanza”: Piero Guccione, Lorenzo Tornabuoni e Giovanni Checchi in Libia”. In La memoria dell’arte. Le pitture rupestri dell’Acaus tra passato e futuro, edited by S. Di Lernia and D. Zampetti, 55-78. Firenze: All’Insegna del Giglio, 2008. Websites

Future prospects undoubtedly invite us to open the doors to research projects oriented to the definition of a standard language.

Lupos3D GbR, Wollankstraße 119, 13187 Berlin, Germany. www.lupos3d.com The Blender Foundation (2002) is an independent public benefit organisation. Its spin-off corporation Blender Institute (2007) hosts the foundation’s offices and currently employs 24 people who work on the Blender software and creative projects to validate and test Blender in production environments. www.blender.org

Bibliography Amoretti, G. and Varani, N. Psicologia e geografia del turismo: dai motivi del turista all’elaborazione dell’offerta. Padova: libreriauniversitaria.it Edizioni, 2016. Arrighetti et al. “Documentazione archeologica e comunicazione “diversificata”: proposte e riflessioni dall’integrazione di software high-cost e open-source”. In Archeologia Virtuale: comunicare in digitale. Atti del III Seminario Roma, 19-20 giugno 2012, edited by S. Gianolio,1985-1994. Roma: Espera srl, 2013.

Official web page of Unity. www.unity3d.com Fasti Online. A database of archaeological excavations since the year 2000 http://www.fastionline.org/.

Barberini, C. AutoCad e il rilievo archeologico digitale. Perugia: Morlacchi Editore, 2006. Campana, S. and Francovich, R. (eds). Laser scanner e GPS. Paesaggi archeologici e tecnologie digitali. I Workshop Grosseto, 4 marzo 2005. Firenze: All’Insegna del Giglio, 2006. Ciabarra, C., Di Fraia, T., Furiassi, G., Palmerini, G. and Vianello, A. “The “Pietra delle Croci” di Lettopalena (Chieti, Abruzzo): first reproductions and investigations”. In Book of abstracts of 20th International Rock Art Congress Ifrao 2018 “Standing on the shoulders of giants / Sulle spalle dei giganti” Valcamonica – Darfo Boario Terme (BS) 29 Agosto – 2 Settembre 2018, edited by M. Giorgi, 498. Capo di Ponte (BS): Edizioni del Centro, 2018. Di Fraia, T. and Manzi, A. “Nuove scoperte di arte rupestre preistorica in Abruzzo”. Preistoria Alpina, 46 II (2021): 109-117. Museo delle Scienze, Trento. Di Fraia, T. “Le raffigurazioni rupestri della Parete Manzi di Montelapiano (Chieti) e quelle del Cavone di Spinazzola (Bari)”. In XLVII Riunione Scientifica IIPP in Puglia. Ostuni (BR), 9-13 ottobre, 2012. 61

6 Digital documentation of Ancestral Pueblo and Ute rock art in the Canyons of the Ancients National Monument, Colorado (USA) Radosław Palonka, Bolesław Zych Abstract Our chapter focuses on different techniques of digital documentation, such as photogrammetry and laser scanning as well as subsequent analysis in a virtual environment of Native American (Ancestral Pueblo culture and historic Utes) rock art and Euro-American settlers “historical inscriptions” from the central Mesa Verde region, southwestern Colorado, USA. Special focus was put on the extracting elements invisible to the “naked-eye” by using high-resolution photo documentation and 3D digitization – via photogrammetry, Reflectance Transformation Imaging, and DStretch software. Also, we briefly discuss the potential benefits and disadvantages of using specific methods in field research, mainly in terms of photogrammetry, laser scanning, and RTI analysis. Keywords Ancestral Pueblo and Ute rock art – image processing – image rectification – Reality Capture – V-RTI 6.1 Introduction

or IFRAO – The International Federation of Rock Art Organisations, to mention just a few).

This chapter presents some results from our research on Native American rock art from several canyons in the southwestern part of Colorado (USA) focusing on the various types of digital documentation that we used – mainly photogrammetry and Terrestrial Laser Scanning (TLS) – and a subsequent analysis with different software, including Agisoft Metashape, RealityCapture (RC), Reflectance Transformation Imaging (RTI) and others. The use of modern forms of digitisation including different types of photogrammetry and laser scanning is now widely applied in various archaeological projects focusing on rock art documentation (e.g., Fröhlich and Mettenleiter 2004; Historic England 2017; 2018a; MacDonald 2014; Remondino and Campana 2014) and has been the subject of various conferences and symposia (see, for example, particular proceedings from the CAA-Computer Applications and Quantitative Methods in Archaeology and ISPRS Archives – The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences proceedings

These techniques allow us to document and analyse petroglyphs and paintings (pictographs) and look more thoroughly at the context of ancient cultures and societies. In our case it also enabled us to capture and visualise some details and motifs that are difficult or even impossible to document by using traditional methods of documentation alone and that could not be seen with the naked eye. We investigated this type of visualisation by using DStretch software (based on the Decorrelation stretch-DS technique, e.g., Gillespie 1992; Gillespie et al. 1986), which is probably the most commonly used nowadays for the enhancement of rock painting images (e.g., Harman 2008; Le Quellec et al. 2013; López et al. 2016) and can also be combined with other methods and “new” technologies in rock art documentation (e.g., Quesada and Harman 2019, see there for further literature). To enhance a few rock art panels (mainly petroglyphs) we also used the Reflectance Transformation Imaging technique (RTI), also known as Polynomial Texture Mapping (PTM) (CHI 2020; Earl et al. 2010; Historic England 2018b; MacDonald and Robson 2010; Malzbender et al. 2000; 2001). The research project is centred around the Lower Sand Canyon area, in the Montezuma County, southwestern Colorado in three canyons: Sand Canyon, East Fork of Rock Creek Canyon and Graveyard Canyon and our second research area is Sandstone Canyon located roughly 16 kilometres northwest from the Lower Sand Canyon locality. All are part of the Canyons of the Ancients National Monument, a legally protected area managed by the US Bureau of Land Management. The canyons in the first research area (Lower Sand Canyon-Figure 6.1) 63

Radosław Palonka, Bolesław Zych

Figure 6.1: Project research area 1 within the Canyons of the Ancients National Monument, Mesa Verde region, southwestern Colorado (USA) (drawing by M. Znamirowski on the basis of USGS/United States Geological Survey data and Project own research).

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Digital documentation of Ancestral Pueblo and Ute rock art contain the remains of forty small sites including wellpreserved cliff dwellings with some sandstone architecture and rock art, as well as one large site or the community centre – Castle Rock Pueblo (Site 5MT1825); all these sites probably functioned as a community of allied sites during the 13th century CE (e.g., Ortman 2008; Palonka 2011; 2017; 2019; Palonka et al. 2020; 2021; Varien 1999). The elevation of the study area ranges between about 1550–2100 m above sea level, with most of the sites located between 1650–1800 m.a.s.l. The second research area, Sandstone Canyon is located at an elevation of c. 1650–1700 m.a.s.l. and includes several sites with huge rock art panels on the canyon walls and dated to different periods, from c. 500 BCE until the turn of the twentieth century CE; they were created by various Native American cultures and tribes, mainly Pueblo and Utes (Cole 2005; Palonka 2016).

details in every picture). For 3D laser scanning research, we used the Faro Focus 3D S120 phase scanner and maps of the sites were prepared using the Topcon OS-103 and Topcon GPT 3007N tachymeters, RTK Trimble GPS and AutoCAD and CorelDRAW Graphic software as well as ArcGIS Pro. With the aim of enhancing some of the less well-preserved rock art panels (both petroglyphs and paintings), we later analysed them in a virtual environment using different software, including mainly Agisoft Photoscan/Agisoft Metashape, PhoToPlan, Photoshop, CorelDRAW, DStretch and Reflectance Transformation Imaging (RTI). The latter (RTI) is “a computational photographic method that captures a subject’s surface shape and colour and enables the interactive re-lighting of the subject from any direction” (http://culturalheritageimaging.org/ Technologies/RTI/). Although perhaps not widely used (e.g., Duffy 2018a; 2018b; Earl et al. 2010; Mudge et al. 2006; Pires et al. 2015; Solem and Nau 2020, see there for further literature), it did in fact help us enormously in terms of enhancing and interpreting some details of the rock art panels by varying the position of the light in a virtual environment, especially a technique that we may call V-RTI, what means virtual RTI. This method was developed, probably independently in only a few places in the world, including by one of the authors of this paper, Bolesław Zych).

Our research has been conducted since 2011 by the Sand Canyon-Castle Rock Community Archaeological Project led by the Institute of Archaeology at the Jagiellonian University in Kraków (Poland) with the cooperation and help of several American institutions, mainly Canyons of the Ancients National Monument and Crow Canyon Archaeological Centre. Great emphasis has been placed on digitisation and different digital techniques of documentation, including photogrammetry (also photogrammetry from a UAV/drone) and terrestrial laser scanning (TLS), which have allowed us to document the rock art, especially when located in hard-to-access places like cliff alcoves and shelters. Using non-invasive techniques, archaeologists from Krakow have partially or fully surveyed thirty out of around forty of the small Ancient Puebloan sites in the project research area.

In the case of rock art, the above-mentioned modern methods of digitisation brought the most changes in the documentation process and later analysis, providing and revealing data and details that often could not be observed by the naked eye or obtained by hand drawing or ordinary photography alone (e.g., Palonka et al. 2021). Later, some simulations and visualisations were run using different software and equipment, including animations and movies. We also created virtual models of some of the rock art panels documented during our work. One three-dimensional model of a rock art panel from Site 5MT129 in Sand Canyon can be seen on the Sketchfab-website: https://sketchfab.com/radek.palonka; https://e-sandcanyon.org/ the model is shown in colour and greyscale. Part of this work, including a multimedia rock art presentation, was displayed at two museum exhibitions: in 2019 at the Canyons of the Ancients Visitor Centre & Museum, Dolores (Colorado) and in 2020 at the Edge of the Cedars State Park Museum (Utah). Appropriate presentation, publication and different forms of virtual reconstructions and visualisations of rock art is also the focus of our research.

6.2 Methodology and Equipment Rock art as well as murals and examples of “modern graffiti” were partly recorded by the field crew and students involved in the research via hand drawing as well as, to a great extent, digital photography and photogrammetry. For accurate measurements, recording the location and layout of the sites as well as the relation of the rock art panels to the architecture, settlements, and the surrounding landscape, we used electronic tachymeters/total stations, GPS RTK and 3D terrestrial laser scanning (TLS), along with photogrammetry from a UAV/drone. Rock art panels located in inaccessible locations or extremely fragile were documented exclusively via digital photography, photogrammetry, and laser scanning; they were later drawn, mostly via CorelDRAW Graphic software.

6.3 Digital Photography, Photogrammetry, and Laser Scanning

The equipment varied according to season but included few digital cameras used for photogrammetry and photography – mainly NIKON D700 and NIKON D7100 with 24-, 35-, and 55-mm lenses (photos in jpeg/tiff formats); we also initially used the SONY A7RII camera with 35- and 55-mm lenses and a 42,4-megapixel CMOS back-illuminated sensor (this sensor enhances light collection efficiency while minimising image noise, in order to reveal fine

For the documentation of rock art sites, we used at least two different photogrammetric techniques. The first uses multiple overlapping images (horizontal, vertical as well as parallel and convergent images to minimise the systematic errors) that provide the coverage necessary to reconstruct the 65

Radosław Palonka, Bolesław Zych entire object (rock art panels in our case). The data can then be analysed via different dedicated software like Bundler, Photomodeler, Pix4D mapper, and Agisoft Photoscan (now Agisoft Metashape), and many others (see for example Historic England 2017); we use the latter, which is one of the most popular on the market. We have conducted photogrammetry with this method at several rock art sites in the community. The other method is the single image rectification technique that is discussed later in this chapter.

for creating a 3D model generated along with surface vector maps – normal maps and global lighting maps, similarly to other investigations conducted by different scholars (e.g., Štuhec 2017). In order to emphasise and reveal the characteristic features of the surface, ambient occlusion maps were generated, which showed surface irregularities in grey scale. In this way, it was possible to emphasise the shapes that outline the individual elements of the petroglyph; however, the surface from the laser scanning and after the triangulation process was very noisy, and did not provide a satisfactory result, however, it bore fruit thanks to photogrammetry. Then it was visualised in the RTI viewer (Figure 6.4) where we obtained a model with a very accurate surface, without much noise, showing elements that had previously been barely visible or invisible – the outline of an unfinished spiral, made as a series of punctures on the surface of the rock as well as other motifs. Also, the ability to change the lighting, its direction, intensity, reflection from the surface as well as various types of filters, enabled accurate analysis of the petroglyph (for more description of the RTI/V-RTI technique see below).

6.3.1 Multiple images photogrammetry and 3D scanning We used this technique for the few sites with petroglyphs mainly. The example is Site 5MT129, located in a cliff alcove (shelter) in a branch along the east side of Sand Canyon (elevation of the site is 1795 m.a.s.l.). It is a cliff dwelling settlement with several domestic and religious structures (at least two rooms and two kivas–Figure 6.2); the site faces directly south. Rock art at this site involves a panel with three-spiral petroglyphs along with other geometric motifs like lines, dots, and cupules. The left spiral is only barely visible, while the right spiral has been interpreted as possibly resembling a snake, also based on analogies to other sites in Arizona and Utah. The spiral motif can have a variety of meanings to modern Pueblo people, and is often interpreted as being related to migration, or could be connected with water and sun symbolism, as well as astronomical observations. The rock art panel was documented using digital photography and photogrammetry, and with terrestrial laser scanning (TLS) followed by analysis using Agisoft Photoscan and RTI (Reflectance Transformation Imaging) software.

6.3.2 Single image rectification photogrammetry of large panels in Sandstone Canyon A different photogrammetry method known as image rectification1 was used to document huge rock art sites or galleries in Sandstone Canyon. Since 2014 the documentation of several rock art sites located in Sandstone Canyon, approximately 16 kilometres northwest of the first/main research area (Sand Canyon and East Fork of Rock Creek Canyon), was also initiated on the invitation from the partner Institution that also manages the area, the Canyons of the Ancients National Monument/US Bureau of Land Management. During the course of several years of surveys and documenting the southwestern part of Sandstone Canyon, we were able to make an inventory of rock art panels (mostly petroglyphs) of one site previously known and this also led to the discovery of four previously unknown sites with rock art and their subsequent documentation. The largest site with rock art is Site 5MT13288 (Strawman Panel Site/Painted Hand Petroglyph Panel) (Figure 6.5); it is a 130-metrelong canyon wall almost full-covered with rock art (mostly petroglyphs) dated to different time periods (Cole 2005; Palonka 2016). The highest part of this cliff wall is 1667,56 m.a.s.l. and the bottom or modern ground surface is 1641 m.a.s.l. (at its highest point the wall is 26 m), and the petroglyphs are located up to c. 3 metres above the modern ground surface. There is a metal fence that runs across the whole length of the wall and at the distance of c. 3 m from it to protect the petroglyphs from vandals and animals, mostly cows from the nearby cattle ranch.

To acquire better resolution and further details of the rock art panel, we used photogrammetry and Agisoft Photoscan software. The first model was generated in Agisoft from a series of 175 photos taken from a distance of about 2.5 m parallel to the surface, with a Nikon D7100 (f/5.6, ISO–400, 35mm), obtaining a Dense Cloud with point distances at every 1.2 mm on average. The next stage of processing the model was to lower the mesh surface from a high polygonal to low polygonal model for better postprocessing (Guidi and Remondino 2012), and transferring surface vector information by normal maps; thanks to this we don’t lose detail information about the original surface. Next, for the purposes of interpretation in the 3D environment, the light source, its intensity, distance and a series of lighting directions were defined in relation to the analysed model. The next step was the creation of a series of renderings, each with a different panel illumination, and importing them into the RTIbuilder to generate a file that allows us to use a range of available filters and light movement for interpretation purposes. This virtual post processing method we call V-RTI. The site was documented using a laser scanner (TLS) with 42 scanning positions and the petroglyph with 2 scanning positions (Figure 6.3). The point cloud from the rock art (after filtering with 1.5 mm resolution) provided the base

  The process of “rectification involves the projective transformation of a single tilted image to a plane to remove the tilt displacements, optionally including an estimation of lens distortion parameters” (Historic England 2017, 10). 1

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Figure 6.2: Site 5MT129 in Sand Canyon during documentation with a laser scanner (a) and a map of the site with the location of particular buildings and the petroglyph panel (b) (photo by M. Znamirowski, drawing by K. Ciomek, B. Zych).

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Figure 6.3: Comparison of: (a) the resolution from the documentation with laser scanning and photogrammetry and later analysis of the petroglyph panel at Site 5MT129 (by B. Zych); (b) drawing of the petroglyph panel based on photogrammetry, laser scanning, RTI analysis, traditional photos and direct-field observations (drawing by K. Ciomek).

Rock art at this site was initially dated from around 500 BCE, through the first few centuries CE to the end of the thirteenth century CE (the final period of Pueblo culture occupation of this area) and later to the historical period and the appearance of the ancestors of the historic Ute and Navajo Indians in this area. The petroglyphs depict mostly single geometric motifs, clan symbols (the bear paw appears the most often), individual figures of people

and animals, shamans, and extended scenes that include fighting and also the hunting of large animals, mostly deer, bison, and bighorn sheep. Of course, almost every panel of rock art features so-called “modern graffiti” or just vandalism such as initials, names and dates; some of them were left by early explorers and settlers of the area and Mexican and American cowboys passing through the canyon with cattle at the turn of nineteenth and twentieth 68

Digital documentation of Ancestral Pueblo and Ute rock art

Figure 6.4: Petroglyph panel from Site 5MT129 and post processing (after photogrammetry) surface analysis via RTI: (a) RTI Builder interface and (b–e) post processing with a different light direction in V-RTI (virtual RTI) (by B. Zych).

century (we were even able to identify some of the ranchers’ families that their members left these carvings).

documentation process due to the fact that the panels are so large and contain so many depictions that detailed hand drawing would last many months; another factor was the limited access to just one road leading to the site and managed by a private landowner who run a cattle ranch nearby. Photogrammetry was taken using different digital

For the Strawman Panel site, we chose photogrammetry documentation as the main method for several reasons, but mainly because of the short time we had for the 69

Radosław Palonka, Bolesław Zych

Figure 6.5: Examples of the documentation and subsequent drawing of large rock art galleries using single image rectification photogrammetry at the Strawman Panel site (5MT13288) in Sandstone Canyon (by P. Micyk, drawings by K. Ciomek).

cameras (see Methodology section) and plans of the sites were prepared using the electronic tachymeter Topcon GPT 3007N, GPS RTK Trimble (geodetic references were recorded in the UTM 12 coordinate system), the same equipment was used for control points measurements. The information was obtained from single images and by using a process of image rectification, which is one of the simplest ways to achieve this type of documentation (e.g., Historic England 2017, 9–11). Besides documenting the rock art, some geophysics research (mainly GPR and electrical resistivity) and test-pits excavations were conducted at the Strawman Panel Site.

the petroglyph wall (between the fence and the canyon wall); it included photographs taken in the early afternoon (the wall is then in shade and particular depictions are much more visible than in full sunlight); in every photo there were at least 4 markers (mostly more); 2) a second series of photos was taken for the control from a distance of c. 6–7 m and due to the high metal fence the photographs were taken from the roof of a car; 3) a third series of photos was taken from a much longer distance, c. 25 m from the canyon wall for photographic and photogrammetry documentation of the entire cliff wall. The main benefits of the image rectification method are the relatively short time required to gather data, which mainly involves setting up the markers, photographing and recording/measuring all the markers, as well as the low fieldwork cost (besides the geodetic works). The photogrammetry took two days of fieldwork in 2014 and we returned to the site in 2015 to finish some documentation (one day). Also, we had to check our drawings from the photogrammetry and compare them with the petroglyphs at the site (during this check we were able to find an additional c. 40 depictions that were missed from the photogrammetry).

For the photogrammetry documentation, we first positioned control points or markers on the canyon wall between different rock art depictions and panels; white stickers with black dots in the middle were control points; later we recorded them using an electronic tachymeter/total station Topcon GPT 3000N (we used several positions of the total station because of the presence of the fence). The total number of markers was 918 and they were placed up to 2 m above the modern ground surface and in a pattern of 4-5 markers in a “column” at a distance of c. 1 m from one to the next column and partly randomly between those locations; every marker was recorded with X, Y, Z coordinates using the tachymeter and compatible with the UTM 12 coordinate system. The upper edge of the cliff wall was also documented using an electronic tachymeter and control points (around 100 control points/markers were used for recording the upper shape of the canyon wall).

The main part of the documentation process is conducted in the lab (image processing, preparing orthophoto plans and subsequent drawings). For the initial stage of data processing, we used geodetic MikroMap and the rectification was made using software running inside a AutoCAD package like PhoToPlan (the first release of this software as AutoCAD Plugins, later in Autodesk Revit, and now part of the FARO software), although this is quite expensive software; we used AutoCAD Plugin PhoToPlan Ultimate 8. Then we exported the orthophoto plans with detailed scales as pdf files for further drawing using AutoCAD and CorelDraw.

The next step included photographic/photogrammetry documentation of all of the rock art depictions and panels and the canyon wall. The photogrammetry documentation (the measurement of single images and by using a process of image rectification) was conducted in three stages or series of photos: 1) from a distance of c. 2.5–3 metres from 70

Digital documentation of Ancestral Pueblo and Ute rock art The main drawback of this method is that rectified photography is most suitable for planar (flat) surfaces. In our case, the cliff wall is not ideally flat (it is slightly curved but not three-dimensionally complex at all) and we had to overcome this problem – we placed more markers to obtain as many measurements as possible in a single image (more than 900 markers were used in total). The entire cliff wall is 130 metres long so we decided to divide it into nine parts (sectors) to obtain relatively flat surfaces for the photogrammetric/image rectification documentation at every sector that allowed us to avoid typical errors.

6.4.1. Decorrelation Stretch/DStretch

last few years (e.g., Harman 2008; Cerrillo-Cuenca and Sepúlveda 2015; Rogerio-Candelera et al. 2011; Ruiz and Pereira 2014), including probably the most well-known and used in studies of paintings, so-called DStretch. We used this technique for the few sites with pictograms (paintings) as well as coloured murals from the building’s walls; in a few cases we also tried to use this technique in connection with the petroglyphs (for example the Site 5MT22149/Sandal Panel in Sandstone Canyon). Below there is the example from Site 5MT264 (The Gallery), located in East Fork of Rock Creek Canyon (Figure 6.6) where DStretch software helped us a great deal in revealing previously unknown depictions, because they are barely visible or invisible to the naked eye or by using traditional photography alone; so, this proved enormously helpful in reading the whole panel.

There are different techniques for digital tracing and enhancement of rock art that have been in use over the

The rock art from the Gallery is located in the central part of the site on the cliff face (facing east/southeast), c.

6.4 Digital Enhancement: Making the Invisible Visible

Figure 6.6: Rock art research at the Gallery site (East Fork of Rock Creek Canyon): (a) documentation of the architecture and rock art panel (upper right) with a laser scanner (photo by R. Słaboński), (b) drawing of the panel based on DStretch analysis (drawing by R. Palonka, K. Ciomek), (c–f) different filters used in DStretch: c–ac, d–lab, e–ldk, f–lds (DStretch enhancement by J. Śliwa).

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Radosław Palonka, Bolesław Zych 2.5–3 metres above the modern ground surface and also above a small natural cave (also with the remnants of a masonry wall probably built in the thirteenth century CE phase of this site’s occupation). The rock art panel consists of paintings of several anthropomorphic trapezoidal and/ or triangular figures viewed frontally and painted in white and red. The most prominent and visible anthropomorph is painted in red, with two arms hanging alongside the torso; another two are painted in white and one has raised hands. This last anthropomorph has a visible, though poorly preserved, headdress, which could only be seen after analysing photos using special filters in graphic programs (we used simply Photoshop in this case). On both sides of the panel there are poorly preserved remnants of some depictions in red; the one to the left is only preserved in fragments and may possibly be a depiction of a parrot or turkey (these could be a later addition).

more widely using digital tools. The use of a 3D environment creates conditions that cannot be used in traditional documentation, i.e., apart from flat 2D representation – drawing and photography – we obtain full surface geometry, which is subjected to colour scale analysis, relief depth, shape analysis using light, simulation of the sun’s impact, capturing details that we would not acquire in traditional documentation. In addition, rendering in a three-dimensional and V-RTI environment eliminates errors resulting from inadequate lighting, intensity, lens aberrations. Renderings from 3D software are always sharp and provide a properly reflected surface. Using V-RTI allows analysis of different types of surfaces, ranging from small elements through terrain with archaeological sites (e.g., Goskar and Cripps 2011), which is impossible with standard RTI due to the surface size. In Lower Sand Canyon there are some quite well-preserved rock art panels exposed to rainfall and sun exposure, e.g. the petroglyph panel at the 5MT129 site and some heavily eroded panels, practically invisible to the naked eye, such as the petroglyph at the 5MT261 site (Figure 6.7). Visualisation of the surface of the three-dimensional models generated from a point cloud of laser scanning and photogrammetry enabled an interpretation of the shape of the petroglyphs and their accurate documentation. The first effects could already be observed at the stage of processing in Metashape using the Model Solid and Occlusion Map functions. The models, however, are displayed without lighting, so their surface is flat and the shapes of the petroglyphs are not sufficiently outlined. Therefore, after generating a series of images with different lighting in a virtual environment and processing them with RTIbuilder, we obtained a surface image emphasising the shapes of the petroglyphs with the help of lighting that changes in real time.

Due to the poorly preserved state of the painting, it is difficult to unequivocally determine what it represents, although we have recently managed to enhance it significantly using DStretch, which also revealed that the middle white figure has some decoration (stripes or other elements) on its torso. After photo enhancement (and zooming the photos on a computer) we could see more anthropomorphic figures painted in white: at least two trapezoidal humans shown in frontally and possibly two other small figures in motion. Furthermore, the red figure probably has a “head” with some kind of elaborated headdress (or mask), possibly in the form of petroglyph and white painting or, more probably, the red trapezoidal anthropomorph superimposes this “mask” (the red figure partly superimposes the white figure to the left as well). All of these depictions from both sites could be perceived as representing the eastern variants of the Basketmaker rock art (probably BM II/early BM III style), also called the San Juan Anthropomorphic style (Cole 2009, 117–43; Palonka 2019, 236–40; Schaafsma 1980, 109–21) that could be roughly dated in this area from 1000/500 BCE to 400/500 CE., with an emphasis on the last centuries BCE or first centuries CE. The interpretation of these rock art panels is difficult but some of these depictions can be seen as representations of chiefs or warriors with plumes or headdresses, or they may represent shamans (Cole 2009; Schaafsma 1980, 109).

Thanks to this, it was possible to analyse a heavily damaged petroglyph at the 5MT261 site, which presents a spiral, a sandal and two feet, invisible to the naked eye (Figures 6.7, 6.8). Access to this petroglyph example is easy because it is located on ground level, but lighting the entire petroglyph panel with the RTI technique is physically difficult due to the nearby rock formation. Furthermore, in the case of the panel from the 5MT129 site, documentation is difficult due to its size and location with difficult access to it. Therefore, the only solution was to use non-invasive digitisation with laser scanning and photogrammetry to obtain images in orthogonal projection. The two-dimensional image analysed in RTI comes from the rendered surface of the three-dimensional model, and it is a reflection of the surface obtained as a result of point cloud post processing; it was not generated directly from photos obtained when photographing the petroglyph surface with different lighting according to CHI (Cultural Heritage Imaging – CHI 2020) processes. The result is satisfactory, despite the modification of the process, and depends on the density of the point cloud on whose basis the three-dimensional model for analysis was created. All edges, abrasions and punctures on the surface

6.4.2 RTI – Reflectance Transformation Imaging Considering the difficulties in applying the RTI process in the field in this case, we used a virtual environment (Historic England 2018b). That afforded us full light control – direction, intensity, type. In this way we eliminated errors that could occur during the capturing process using a traditional RTI method in the field, as may be noticed with normal map filtering. We used RTI technique mostly for the analysis of the petroglyphs. Scanning and photogrammetric data gave the opportunity to reproduce a virtual surface, which could be interpreted 72

Digital documentation of Ancestral Pueblo and Ute rock art

Figure 6.7: Rock art at Site 5MT261 in Sand Canyon: (a) view of the site and location of petroglyphs, (b) photo of a rock art (petroglyph) panel, (c) visualisations based on photogrammetry and RTI revealing some details not visible to the naked eye (photos by M. Znamirowski; photogrammetry and RTI analysis by B. Zych).

are visible, as well as processes related to the formation of the petroglyph and its erosion.

combining individual elements into one complex. Data of this type allowed us to integrate architecture, rock art and the selected landscape features with precise locations and geographic coordinates. Combinations of data from laser scanning, photogrammetry and UAV photogrammetry were processed using RealityCapture (RC) software, which enabled automatic merging of files in the form of RGB images, recognising the correlation between overlapping

6.5 The Bigger Picture: Laser Scanning, Drone (UAV), and Digital Elevation Models Capturing photogrammetric and scanning data facilitated the documentation of selected sites in a broader context, 73

Radosław Palonka, Bolesław Zych

Figure 6.8: Details of the rock art panel surface from Site 5MT261 using different software: (a) RealityCaptures, Blender, Photoshop, RTI Builder; (b,c) RealityCaptures, Blender; (d) Agisoft Metashape, Blender, Photoshop; and (e,f) Agisoft Metashape, Blender, RTI Builder (prepared by B. Zych).

data and identifying coexisting elements regardless of how they were obtained, including laser scanning data.

– lintels, fingerprints in plaster) using high-resolution photogrammetry, connected with the topography of the area obtained by registering the closest surroundings with laser scanning and UAV photogrammetry. Data integration was supported by control points measured in the WGS84/ UTM12 coordinate system, as well as by characteristic points within the architecture, which enabled their precise

This type of digitisation of the sites makes it possible to document them at various levels of detail, focusing on the layout of the architecture itself obtained by scanning, supplemented with details (rock art, construction elements 74

Digital documentation of Ancestral Pueblo and Ute rock art connection. In addition to orienting the point cloud in the geospace, checkpoints allowed clusters – consisting of a group of photos that were not automatically integrated – to be connected manually.

observing changes in light and shade on several examples at the same time, using a 3D environment such as Blender, or a game engine of for example Unity or Unreal Engine 4. 6.6 Conclusions

This is also important for projects with a large amount of data (5MT135 – 10500 photos and fls files, 5MT261 – 7600 photos/fls files), because it allows us to work with smaller amounts of data divided into groups, thus streamlining data processing. The classification of the area and the separation of vegetation allowed it to be removed, which in some cases disturbs the visibility and the correlation between architecture and rock art (5MT261 – trees obscuring the view of alcove with the architectural remains). The geometry (shape and layout of walls, remains of buildings) of some sites (5MT135, 5MT261) was recorded using three different techniques to document objects depending on their characteristics, using scanning and photogrammetry for architecture and rock art, and the topography of the surrounding area with UAV photogrammetry. Other sites with a more integrated structure were documented by scanning and photogrammetry exclusively – 5MT129, 5MT1805. Thanks to this, we have obtained a spatial image of the sites that allows accurate documentation in correlation to other structures in a specific coordinate system.

This chapter presents some results from research conducted in the canyons of the southwestern part of Colorado, USA focusing on digital documentation, mainly laser scanning and photogrammetry as well as a subsequent analysis, using a variety of software, of rock art created by several Native American cultures and tribes during different periods. The research area mainly encompasses three canyons located in the so-called Lower Sand Canyon locality, with Ancestral Pueblo culture architecture and rock art along with huge rock art panels and sites in Sandstone Canyon (located 16 km northwest of the first area) containing Ancestral Pueblo, possibly Fremont, and historic Ute’s rock art. The total chronology of Ancestral Pueblo rock art panels runs roughly from 500 BCE to 1300 CE (mostly the thirteenth century CE) in this area and more recent Ute Indians petroglyphs have been dated to the seventeenth –nineteenth century; there are also many examples of “modern graffiti” and vandalism at those sites left by early explorers, settlers and Mexican-American cowboys passing through the canyons at the turn of the twentieth century.

An example is Site 5MT135 (Sunny Alcove), where inside the niche, apart from architecture, there are examples of rock art along with a nearby tower (Site 5MT13446) at a distance of about 120 m to the south, to the south-east. And on the other side of the canyon, about 200 m away, stands the 5MT2796 site (a shrine). The second site, consisting of interconnected structures and rock art, is Site 5MT261, next to which there is a tower on the west side, and a stone with a petroglyph was discovered south of the rock shelter. Thanks to accurate documentation, we can observe the mutual relations between them, while it is also possible to perform simulations to study the rock art, the influence of the sun on the petroglyph as well as the architectural elements or the edges of the alcove for example using ArcGIS software (Figure 6.9), creating a model of the interaction, which would be not possible without creating three-dimensional models from digitisation data.

The aim of documenting rock art from this region was to produce a detailed inventory of this cultural heritage (apart from our other activities aimed at researching the settlement structure). Another goal was to check the efficacy of various digitisation methods in the documentation of rock art and subsequent analysis of the obtained data in a virtual environment in order to better understand paintings and petroglyphs damaged or obliterated by the passage of time and weather conditions. We used various techniques for this: various methods of photogrammetry, laser scanning, geodetic measurements and virtual enhancement using DStretch and RTI (Reflectance Transformation Imaging) techniques. The data recorded have been used to generate accurate 2D documentation together with 3D models with special focus, among other things, on extracting elements invisible to the naked eye by using high-resolution photo documentation and three-dimensional digitisation. The 3D models that were generated have been used to interpret some depictions – for example, petroglyphs – via photogrammetry and RTI software (plus an additional method – DStretch) to enhance particular images. We used this method to analyse rock art at sites 5MT129 and 5MT261 from Sand Canyon, for example.

The use of three-dimensional models and the Numerical Terrain Model generated on the basis of a point cloud enables simultaneous real-time tracking of changes in lighting and correlation between sites and rock art. An example here are sites 5MT129, 5MT261, where the discovered petroglyphs are located outside the alcoves with the architecture and at a certain distance from it. The virtual environment enables the simultaneous observation of various selected elements, creating a lighting simulation, as well as the observation of this process within the reconstructed elements of architecture. It is also possible to create a three-dimensional map of the actual examples of rock art from different positions and thanks to the exact knowledge of the geographic location and the surrounding landscape, we can create a simulation by

Also, virtual data processing may be a solution for other documentation techniques, whose application in the field may be difficult. Changing some processes like RTI and transferring them to a virtual environment (VRTI) facilitates data capturing in the field, regardless of form and independent of weather conditions. At the same time, in the virtual environment, we gain full control over the lighting and the quality of the generated images. 75

Radosław Palonka, Bolesław Zych

Figure 6.9: Digital Surface Model (DSM) of Site 5MT261 using ArcGis Pro software: (a) showing the location of the rock art (marked with a square) in relation to the cliff dwelling and terrain; and (b-e) simulations of petroglyphs illuminated by different light/sunlight positions: (b) light from the east: azimuth 90, angle 45˚; (c) light from the southeast: azimuth 135, angle 45˚; (d) light from the south: azimuth 180, angle 45˚; (e) light from the southwest: azimuth 225, angle 45˚ (by B. Zych).

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Digital documentation of Ancestral Pueblo and Ute rock art Documenting hard-to-reach and large areas of rock art becomes also possible in a relatively short time. The V-RTI technique was developed and adjusted to specific field conditions from the project research area by one of the authors of this chapter, Bolesław Zych (we know that development of this method was probably independent in only a few places in the world).

art and macro-scale study of terrain with the relation to particular rock art panels; Also, it is possible to overlap or to complement different techniques like V-RTI, DStretch, otophotoplanes, in our cases. Acknowledgments Our research on rock art and its digital documentation in the Canyons of the Ancients National Monument, Colorado (USA) was made possible thanks to the help of many institutions and individuals. We are sincerely thankful to our American partners, the Canyons of the Ancients Visitor Centre & Museum/US Bureau of Land Management and Crow Canyon Archaeological Centre. This research was made possible by the financial support of numerous institutions, mainly the Institute of Archaeology and the Faculty of History of the Jagiellonian University in Kraków, and especially the National Science Centre, Poland (grant UMO-2017/26/E/HS3/01174). We also thank the former Dean of the Faculty of History at JU, Prof. Jan Święch and Vice-Rector of the Jagiellonian University, Prof. Armen Edigarian for the possibility of acquiring important hardware and software for gathering digital data and subsequent analysis. Thanks also to Patryk Muntowski and Paweł Micyk (from the Galty company) for conducting and processing part of the photogrammetry documentation.

Depending on the scale of the object and its context, various digital methods also offer different possibilities for documentation and analysis of individual objects (particular rock art depictions and whole panels) and large panels or galleries (such as the 130-metre Strawman Panel Site in our case) in the wider context of the surrounding landscape. Documentation and analysis of archaeological sites via the use of several different non-invasive methods create new research possibilities by combining data. Fast and mobile UAV documentation of large spaces allows digitised sites to be combined with rock art and landscape. This enables us to obtain an accurate plan of the site along with various details, e.g., rock art and precise topography of the area, which then helps to build a GIS database including the exact location of all architectural remains, even within large spaces. In addition to documentation, it is possible to conduct simulations, for example, of sun lighting of the rock art panels (that could help in terms of potential archaeoastronomical analysis), or hydrological simulations showing water courses.

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So, a further motivation of our project works was to integrate and present the spatial and cultural relations between rock art panels, dwelling sites (mostly cliff dwellings and towers) and the surrounding terrain and landscape (mountains, plateaus), which were important in the belief-system of Native American communities once living there and were also depicted in the rock art; these analyses were conducted via RealityCapture (RC) and ArcGIS Pro, among other techniques. Another element are the virtual three-dimensional models that we used in Digital Elevation Models (DEM) and Digital Surface Model (DSM) that include the rock art sites as well as the associated architecture and environment. Last but not least, all of the above would culminate in an accurate publication of the acquired digital data on the Internet, for example at the Sketchfab website and similar platforms and in an accurate way in printed form.

CHI –Cultural Heritage Imaging, http:// culturalheritageimaging.org/Technologies/RTI/ (accessed 15 December 2020). Cole, S. J. 5MT13288 Site or Property Revaluation Form. Prepared for the Anasazi Heritage Center/Canyons of the Ancients National Monument, Colorado, 2005. Cole, S. J. Legacy on Stone: Rock Art of the Colorado Plateau and Four Corners Region. Boulder: Johnsons Books, 2009. Duffy, S. M. “Case Study 2: Daytime survey of prehistoric rock art at Roughting Linn, Northumberland”. In Multilight Imaging for Cultural Heritage, edited by Historic England, 36–38. Swindon: Historic England, 2018a.

On the basis of the results of our research and on analogies from similar studies conducted by various projects we can also conclude that the application of particular techniques of digital documentation and analysis of the data in the virtual environment depends mainly on the aims we wish to achieve or the research questions to be answered as well as on the funds and time available for the fieldwork and subsequent lab work and data analysis. Sometimes various techniques and methods and software provide similar data (for example photogrammetry and RTI technique) that is later used for different purposes. The flexibility of digital documentation and subsequent processing of data allow it to be used for both micro-scale analyses of rock

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Digital documentation of Ancestral Pueblo and Ute rock art Quesada, E. and Harman, J. “A step further in rock art digital enhancements. DStretch on Gigapixel imaging”. Digital Applications in Archaeology and Cultural Heritage, Volume 13 (2019): e00098. Remondino, F. and Campana, S. (eds). 3D Recording and Modelling in Archaeology and Cultural Heritage: Theory and best practices (BAR Publishing 2598). Oxford: BAR Publishing, 2014. Rogerio-Candelera, M.A., Jurado, V., Laiz, L. and SaizJimenez, C. ``Laboratory and in situ assays of digital image analysis based protocols for biodeteriorated rock and mural paintings recording”. Journal of Archaeological Science 38, no. 10 (2011): 2571–2578. Ruiz, J.F. and Pereira, J. “The colours of rock art. Analysis of colour recording and communication systems in rock art research”. Journal of Archaeological Science 50 (2014): 338–349. Schaafsma, P. Indian Rock Art of the Southwest. Albuquerque: University of New Mexico Press, 1980. Solem, D.-Ø.E. and Nau, E. “Two New Ways of Documenting Miniature Incisions Using a Combination of Image-Based Modelling and Reflectance Transformation Imaging”. Remote Sensing 12 (2020): 1626. Štuhec, S. “3D Digital Recording: Basics”. In 3D Digital Recording of Archeological, Architectural and Artistic Heritage, edited by J. Zachar, M. Horňák, and P. Novaković, CONPRA, vol. I. 15–17. Ljubljana: University of Ljubljana, 2017. Varien, M.D. Sedentism and Mobility in a Social Landscape. Mesa Verde & Beyond. Tucson: The University of Arizona Press, 1999. DOIs for additional online material: https://doi.org/10.30861/9781407360119/ch6-image1 https://doi.org/10.30861/9781407360119/ch6-image2 https://doi.org/10.30861/9781407360119/ch6-video1 https://doi.org/10.30861/9781407360119/ch6-video2 https://doi.org/10.30861/9781407360119/ch6-video3 https://doi.org/10.30861/9781407360119/ch6-video4 https://doi.org/10.30861/9781407360119/ch6-image3 https://doi.org/10.30861/9781407360119/ch6-image4 https://doi.org/10.30861/9781407360119/ch6-3Dmodel1 https://doi.org/10.30861/9781407360119/ch6-image5 https://doi.org/10.30861/9781407360119/ch6-image6 https://doi.org/10.30861/9781407360119/ch6-image7 https://doi.org/10.30861/9781407360119/ch6-image8 https://doi.org/10.30861/9781407360119/ch6-video5

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7 Close encounters of the third dimension: recording the threedimensionality of the “topographic representations” in the prehistoric rock art of Valcamonica and Valtellina (Italy) Angelo Martinotti, Alberto Marretta Abstract In the figurative repertoire on outcropping rock surfaces of the Central Alpine rock art, the “topographic representations” – abstract compositions of geometric figures commonly considered as depictions of landscapes – are one of the most enigmatic subjects. As they appear as juxtapositions of modular elements often arranged in articulated complexes, these representations show several solutions for conforming to the morphology and the natural unevenness of the rock support. This is a peculiarity that the traditional recording method used for rock art, the manual tracing on transparent sheets, fails to render successfully due to its bi-dimensional setting. This study proposes the application of the Structure from Motion (SfM) photogrammetric range imaging technique to a selected sample of “topographic representations” from Valcamonica and Valtellina in order to record their three-dimensional features connected to the rock surface and to analyse the meaning of this relationship. Keywords Central Alps – Prehistoric Rock Art – Topographic Representations – Threedimensional recording – SfM 7.1. Introduction

provide an accurate replica of the three-dimensional morphology of the rock surface conveying carved or painted images. The impact of the third dimension is in fact a central aspect of rock art recording which regrettably have never been properly addressed by the classic methods of documentation (photography, paper rubbing and especially tracing on transparent plastic sheet) of rock art, especially in the Valcamonica and Valtellina areas.1 The traditional tracing on plastic sheets of the underlying images, a methodology quite efficient and still widespread in central alpine rock art research, returns a range of twodimensional data from the surface.2 This method takes care chiefly of the recording of the artificial elements (the carved images), limiting natural features to the essential (mostly the main fractures, sometimes the glacial streaks) without taking into account the shape of the overall rock surface.

In the field of rock art studies, the last decade attested a widespread implementation of 3D documentation procedures based on stereo-photogrammetric techniques. Despite the limitations of this methodology in terms of accessibility and dissemination in traditional printed media, which is still the most widespread means for scientific publications, these approaches eventually

However, in Valcamonica and Valtellina the distinctive morphologic characteristics of the rocks compel the adoption of complementary documentation techniques for properly illustrating their elaborate three-dimensional structure. On the rocks of these two valleys the effects of the Pleistocenic glacialism have been strikingly preserved, with outcrops modelled by the intense process of exaration performed by the massive pressure and movement of the  A critical view on digital and traditional methodologies applied in central alpine rock art is in Arcà et al. 2008 (now outdated). Further, more recent considerations in Arcà 2016, 273–287. A case study with application of a 3D SfM technique in Valcamonica in Medici and Rossi 2015. An effective and advanced integrated documentation system, unfortunately quite difficult to apply over large surfaces, has been proposed for carved monoliths in Rondini 2018. 2  Arcà et al. 2008, 355–360; Arcà 2016, 273–277; Marretta 2018, 63–70. 1

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Angelo Martinotti, Alberto Marretta ice sheets during the last glacial stages. Roches moutonnées abound, and the surfaces, often intensely “sculpted” by nature in smooth and plastically moulded forms (called by geologists ``p-forms’’: Hugget 2011, 263–271), are punctuated not only by fractures and detachments, but also by striations, grooves, channels, curvy ridges, crests, hollows and bumps.

accompany them, do not represent constituent elements but juxtaposed additions. Furthermore, these surrounding motifs are often indirectly associated and possibly not in phase, thus irrelevant or useless to clarify the meaning of the whole. To date, nevertheless, the topographic hypothesis remains the only valid exegetical proposal in the absence of equally or more convincing alternatives. The use of modular elements of regular geometric form has thus favoured the principle that recognizes in the iconography of the “topographic representations” an idealised translation of the ancient landscape, centred on the exclusive artificial components introduced by the human activity (cultivated fields, enclosures, cattle pens, huts: Gavaldo 1995; Turconi 1997).

It is therefore not infrequent to find a direct relationship between the carved motifs and the three-dimensional features of the underlying bedrock. The natural characteristics of the surfaces were exploited by the rock art creators as guiding elements to arrange figures, organise scenes and distribute figurative groups (Marretta 2018, 96). Such a systematic phenomenon suggests that the geological and morphological qualities of the rock outcrops have in some way inspired the emergence and subsequent development of a figurative tradition which lasted from the late Neolithic (about 4000 BCE) until modern times.

On the chronological front, there is fortunately less speculative data. Rare but significant cases of superimpositions of images datatable with good confidence to a central phase of the Chalcolithic (style III A1: 3000-2500 BCE: terminus ante quem) recorded on decorated monoliths and on rocks in Valcamonica assign an early beginning of the topographic subject falling in an unspecified moment of the 4th millennium, in the late Neolithic-Early Chalcolithic 1 phases (3800-3400 BCE). Some rock palimpsests with topographic images produced in different superimposed phases demonstrate how the timespan of this oldest chapter of the subject can be divided into two distinct successive moments: phase II A (ca. 3800-3400 BCE), characterised by the incision of large areas of irregular sub-geometric shape with uncertain contours, called maculae, and phase II B (ca. 3400-2000 BCE), marked by greater geometric regularity of topographical modules and by more complex compositions (Figure 7.1a, 7.1b).4 In Valtellina, the longlasting formal development of a peculiar local compound module, the so called “scutiforme” (Italian for “shieldshaped figure”: Figure 7.7), suggests also the existence of a later phase II C, which can be tentatively placed during the early and central phases of the Bronze Age (first half of the 2nd millennium BCE; Martinotti 2009; 2018, 87–91).

In the vast rock art motif repertoire of Valcamonica and Valtellina, there is a specific subject which persistently shows significant connections with the features of the lithic support: it is the so-called “topographic” motif, usually referred in literature as “map motif” or simply “maps”. It is obvious, considering the interpretative importance of this figurative class, that the contribution of the stereophotogrammetric techniques in this particular case does not only have an innovative and advanced documentary value, but rather introduces a new parameter with possibly vital implications on the epistemological and exegetical side. 7.2 The “Topographic Representations” In Central Alpine Rock-Art: An Iconographic and Interpretative Profile With the term “topographic representation” we usually indicate a category of rock art compositions created through the association of various regular geometric figures – mostly rectangles in contour lines or fully pecked, clusters of small cup-marks/dots, connecting lines – repeated in a modular way to form more or less articulated and extended configurations (Figure 7.1). The qualification of “topographic” (or “planimetric”) images attributed to these figurative assemblages derives from the shared opinion that they reproduce, in zenithal view and in a schematic and abstract form, portions of the territory altered by the human activity and thus marked by cultivated fields, fences, pastures and buildings.3 It is, however, an almost conventional interpretation, triggered more by fascination and contemporary aesthetics than by explicit and unambiguous evidence (Marretta 2013). The representations are in fact expressed in the most fixed and abstract geometrism and the few recognizable figures of real motifs (humans, animals, buildings), which sometimes

After a period of rarefaction – or downright interruption – corresponding to the late Bronze Age, the “topographic” motif reappears in Valcamonica during the early Iron Age in new forms, with completely different constituent modules and compositional formulas. This is the phase of the most spectacular and well-known representations, such as the famous “Bedolina map” – actually the leader of a group of very similar images – expressed with a fascinating and almost “baroque” complexity (Figure 7.1c) (Gavaldo 1995; Turconi 1997). In this protohistoric group, more varied, intricate and spacious patterns dominate. They are centred on large reticular structures or on interconnected sets of square modules in a contour line internally filled with neatly  Arcà 1999; 2007, 47–48 with further bibliography; Gavaldo and Sansoni 2016; Martinotti 2018, 87–91. In the absence of undisputed chronological evidence for the beginning of phase II A and its transition to phase II B, we will adopt here the more cautious dating proposed in Fedele 2011, fig. 7. 4

 Arcà 1999; 2007, 36–41; Gavaldo 1995; Marretta 2013; Martinotti 2006; 2009; 2018, 86–100; Priuli 1991, 305–332. 3

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Figure 7.1: Examples of camunnian and valtellinese “topographic representations”: A. Teglio, Villanuova Rock 7 (Copper age); B. Capo di Ponte, Coren di Redondo Rock 12 (Copper Age); C. Capo di Ponte, Bedolina Rock 1 (middle Iron Age). The map on the left shows the position of the two valleys in the Alpine region.

arranged cup-marks/points. Frequent superimpositions with stylistically datable human figures place the chronological span of this late phase of the subject between the early and middle centuries of the Iron Age (8th-4th centuries BCE. Marretta 2013; Turconi 1997).

to the 3D rock surface will possibly cast some light on the nature of this peculiar behaviour and will offer some clues for further interpretation. 7.3 The Third Dimension Challenge: A Phenomenology of the Three-Dimensionality of the Central Alpine “Topographic Representations”

Beyond the typological and chronological variability, some basic characteristics of these compositions have raised doubts about their interpretation in a topographical sense (Marretta 2006; 2013). The main argument stresses the fact that a strictly abstract and geometric appearance, focusing only on the human components of the landscape and excluding the natural ones (rivers, mountains, valleys etc.), tend to compromise the readability of the map itself, undermining the correct understanding of the relationship between the actual landscape and its supposed counterpart represented on the rock surface. Secondly, the close, direct, insistent connection with the morphology of the rock seems in contrast with the assumed planimetric nature of these images. In fact, conforming the figurative elements to the forms of the surface would inevitably have altered the spatial values of the reproduced topography compromising its fidelity and distancing it from reality.

The relationship of the “topographic representations” with the rock surfaces reveal itself on two levels. From a macro-morphological point of view, we can observe an adjustment to the general shape and the three-dimensional morphological structure (concave, convex, concaveconvex, flat) of the panel selected to accommodate the image. The adaptation often concerns the compositional syntax in its totality, either adopting an orientation according to the slope of the surface or inscribing itself harmoniously within the eventual limits of the panel. Moving instead to a micro-morphological point of view we see that these images often follow minute morphological details of the rock surface such as fractures, hollows, glacial channels, etc. The adaptation concerns single modules, groups of modules or minimum sections of the composition. The number of cases considered here has been selected in order to illustrate the main recurring instances, and can be articulated according to the following phenomenological framework.

Precisely in relation to this last point, the use of a methodology enabling the accurate documentation and analysis of the mechanisms of adaptation of the figurations 83

Angelo Martinotti, Alberto Marretta 7.3.1 Macro-morphological adaptations

of this sector. The topographic motif is the result of an assemblage of rectangles often bisected by a vertical segment and organised in a peculiar grid-like syntax. What remains of this representation displays a harmonious orientation following the axis of the rock and the glacial striations (Martinotti 2006, 32; Pace 1972, plates II–III; 1982, 46–48) (Figure 7.3a, 7.3b).

– on a concave surface: Capo di Ponte (BS), Seradina III R. 1. Rock 1 of Seradina III is a large outcrop arising at the west side of the main path of the Seradina-Bedolina Archaeological Park (Capo di Ponte). At the top of the rock runs a long, broad, horizontal glacial gutter, within which two small “topographic representations” are placed (Figure 7.2a, 7.2b). They are composed using a subset of the characteristic modules of the classic Copper Age phase (style II B), such as the “underlined” and fully pecked rectangles and the clusters of small cup-marks (Anati 1982, 263 fig. 272, 266 fig. 275). Both images adhere to an elementary scheme of horizontal alignment conforming to the layout of the glacial grooves, which here were intentionally chosen – considering the large smooth surface available – to accommodate this type of figure.

– on a flat surface: Capo di Ponte (BS), Redondo R. 3. In the centre of the small plateau of the Redondo area (Ruggiero and Poggiani Keller 2014, 98–99) a “topographic” figure was carved onto a rectangular and quite sloping surface with an evenly flat appearance. The composition, consisting of the classic modules of the mature Chalcolithic phase (style II B), organically exploits the space offered by the smooth natural panel by orienting the individual components according to the edges of the rock (Figure 7.3c, 7.3d) (Gavaldo 2001, 139 fig. 119).

– on a convex surface: Capo di Ponte (BS), Seradina III R. 28; Grosio (SO), Dosso Giroldo R. 14.

– on a finite panel: Capo di Ponte (BS), Redondo/Dos Mirichì R. 72.

Rock 28 of Seradina III is a small rock located in a panoramic position at the top of a steep area facing the plain of Cemmo-Pian delle Greppe, site of a ceremonial centre with decorated monoliths dating to the middle-late Chalcolithic (3rd millennium BCE). The visual connection between the site and this rock seems to justify the presence of an unusual iconographic package of Chalcolithic themes5 including Remedello-type daggers, “topographic representations” with rectangles and an intricate meandering pattern which has no other occurrences in the rock art of Valcamonica and Valtellina (Anati 1982, 210–211 fig. 222). The surface is divided into a subhorizontal panel and a short ridge placed at the side of a gully ending in a pit. A small topographical composition is carved along this ridge and follows perfectly the shape of this specific portion of the rock. It consists of a large but rather weathered elliptical element surrounded by three rows of cup-marks, a composite geometric motif and a small rectangle overlapping two Remedello-type daggers (Figure 7.2c, 7.2d).

About one hundred metres South-East from the previous rock, on an intensely fractured horizontal portion of a big and morphologically articulated outcrop, a small “topographic” representation consisting of two subsets of modules aligned with the main axis of the panel has been neatly inscribed inside the little space spared by weathering and exfoliation (Anati 1982, 179 fig. 195). The northern section is composed of fully pecked rectangles flanked by a group of neatly arranged cup-marks, while the southern section comprises a series of the typical “underlined” rectangles (Figure 7.4a, 7.4b). 7.3.2 Micro-morphological adaptations – on bump/protrusion: Capo di Ponte (BS), Seradina II R. 18 (Marretta 2013, fig. 14–15). On a large surface richly modelled in soft forms by the glacier, near a sinuous channel stands a very prominent small ovoid protrusion, on which a very simple “topographic” composition of an unspecifiable period, most likely Chalcolithic, has been engraved. The figure consists of an elliptical contour line that follows the shape of the surface perfectly (Figure 7.4c, 7.4d). Inside the contour, inscribed on the top of the protrusion, another elliptical contour line, concentric to the previous one, contains a group of small cupmarks, one surrounded by a rectangle. The composition was clearly born as a figurative complement to the protrusion, filling it completely, and is one of the most evident examples of an image created within a threedimensional morphological element of a rock.

Rock 14 at Dosso Giroldo, in the upper Valtellina, is a rock long whaleback outcrop with a characteristic tapering at the top resulting in a long, convex crest. The surface, modelled and smoothed by the glacial erosion, is located in the centre of a well-known rock art area with figurative and schematic motifs.6 The apical portion and the upper part of the southern flank of the rock have been intensely carved with a large “topographic” image only partly spared by a very dense ensemble of protohistoric cup-marks which literally pierced the entire length

– on concavity: Capo di Ponte (BS), Dos dell’Arca R. 7-sector B.

  Quite rare on rocks, especially in Seradina and neighbouring areas of the western slope of the valley. 6  About this area, one of the richest in rock art in Valtellina, little literature is available; for a selective and preliminary overview of the evidence it is necessary to refer so far to the photographic dossier in Pace 1972, plates I-XVI. 5

The large outcrop emerging on the top of the rocky hill of Dos dell’Arca, seat of a protohistoric site with ritual and 84

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Figure 7.2: “Topographic representations” showing macromorphological adaptation to the rock surface: A-B. Capo di Ponte, Seradina III Rock 1; C-D. Capo di Ponte, Seradina III Rock 28 (untextured mesh view and hillshaded DEM in false colours).

Figure 7.3: “Topographic representations” showing macromorphological adaptation to the rock surface: A-B. Grosio, Dosso Giroldo Rock 14; C-D. Capo di Ponte, Redondo Rock 3 (untextured mesh view and hillshaded DEM in false colours; tracing after Gavaldo 2001).

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Figure 7.4: “Topographic representations” showing macro- and micromorphological adaptation to the rock surface: A-B. Capo di Ponte, Redondo/Dos Mirichì Rock 72; C-D. Capo di Ponte, Seradina II Rock 18 (untextured mesh view and hillshaded DEM in false colours).

productive connotations, is one of the lithic surfaces of Valcamonica that best illustrates the plasticity of the forms of glacial erosion.7 In the southern sector, within a short and deep, optimally smoothed concavity a small, rather incomplete “topographic” composition of the full II B phase is perfectly inscribed. The petroglyph consists of a pecked rectangle with a double base surrounded by a group of small cupmarks partially surrounded by an arched line (Sluga 1969, 34–37 fig. 13). A straight line extends horizontally from the right side of the rectangle. The entire composition harmoniously fits the natural concavity, tracing perfectly part of the inner edge with the arched line (Figure 7.5).

Park (Marretta 2006, 34–39; 2013, 345–346). It is mainly occupied by a large “topographic” representation of the Bedolina type, dating to the full Iron Age (around the middle of the 1st millennium BCE. Figure 7.6). In a peripheral sector of the composition two small groups of satellite modules, connected to each other by a short meandering line, occupy a small depression and a nearby hump in the rock, creating a micro-composition entirely built according to the natural features of the surface (Marretta 2013, fig. 6).

– on concavity and on convexity: Capo di Ponte (BS), Bedolina R. 7.

On a long sheep-backed rock, emerging in the middle of a small slope plateau, four “topographic” compositions of II B style are structured within as many sectors. These are mainly made up – like many representations in Valtellina – by simple juxtapositions of “shield-shaped” modules of the Caven type (Martinotti 2007, 47–53; 2018, 88–91). Sector D, on a short sub-vertical plaque of the eastern section of the rock, consists in a row of six “shield-shaped” figures, five of which are tightly aligned and sometimes merged along the vertical sides. Four of them lie precisely along a slightly oblique natural fracture deepened by glacial abrasion. The groove not only acts as a guideline for the construction of the sequence, but is part of the figuration, to the point of forming the base of the “shield-shaped” figures (Figure 7.7).

– alignment along natural fracture: Grosotto (SO), Bedól sector D.

The large rocky surface re-emerged in 2005 during the construction works of the Seradina-Bedolina Archaeo­logical   Regarding the rock art of Dos dell’Arca: Sluga 1969. In the summer of 1962, the site underwent an extensive excavation campaign (actually earthworks conducted without a stratigraphic method) by the Anati Mission. On the history of research in the area: Rondini 2016. Since 2015 the University of Pavia, under the supervision of prof. Maurizio Harari, started a research project on the hill and in the neighbouring areas, resuming the stratigraphic investigations in areas spared by the Anati excavations: Rondini and Marretta 2019. We are glad to thank Dr. Paolo Rondini, in charge of the excavation, for having consented to the publication of preliminary data. 7

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Figure 7.5: Capo di Ponte, Dos dell’Arca II Rock 7-sector B: particular of the “topographic representation” inscribed inside a groove.

7.4 Conclusions: Setting up a question

morphology of the support and the image had to converge on an ideal preconceived model.

This selected dossier of Valcamonica and Valtellina examples shows for the topographic subject a rather varied and apparently impromptu phenomenology of adaptation to the rocky supports, linked only by the choice of adopting each time the expedients required by the specific circumstances. However, the frequency of this aspect clearly indicates how this was entirely intentional, and how features or particular morphological peculiarities of the rocks were even expressly “sought out” to be exploited – applying the appropriate compositional layout and the graphic solutions – in the construction of the figured composition.

It cannot be overlooked how this kind of characteristic contrasts with the common, modern conception of “map” as a graphic representation of a territory that conforms to reality as much as possible (Schiavi 1997, XV, 27–28). It seems clear how the adaptation of the figuration to the morphology of the rocky surface – both on a general scale and at the level of particular details –, even though the latter might appear evocative of the plastic forms of the territory, could only entail a deformation of the representation, a deviation from an analogical, realistic rendering. A loss of fidelity capable of invalidating any practical functionality. For these reasons, the Authors felt the need to critically rethink the topographical interpretation of these compositions, or at least a strictly realistic notion of them (Marretta 2013; Martinotti 2018, 86 note 31).

It also seems evident that, although the morphological features could be chosen between the innumerable ones present on so variously sculpted surfaces, the figurations must have basically a natural predisposition to fit to them, modelling and conforming consequentially. Therefore, the third dimension had to represent a component strictly connected to the semantic domain of figuration itself, evidence which led some scholars to speak about realistic rock “scale models” rather than “maps” (Priuli 1991, 305; Gavaldo 1995, 167; Casti 2018). In some sense, the “topographic representations” are reduced to “figurative complements” of the rock, made according to the morphology of the surface.

In fact the issue was facing several times in the debate around the interpretation of the abstract alpine rock figures, starting when, in 1897, the Anglican pastor Clarence Bicknell first suggested an analogy between the ‘molte figure rettangolari intieramente scolpite’ (‘many rectangular shapes entirely carved’) he found at high altitude on the rocks of Monte Bego (Maritime Alps, Italian-French border) and ‘piante di case e terreni’ (‘plans of houses and plots of land’) that ‘se fossero state scolpite oggi, si potrebbe dire che sono le Margherie colle baracche dove si fabbricano il burro ed i formaggi’ (‘if they had been carved today, one could say that they are the mountain huts where butter and cheese were made’; Bicknell 1897, 400).

It is impossible to say whether the composition assumed a definitive form following the choice of the morphology of the point chosen to engrave it, or rather an area with morphological characteristics suited to a prefigured compositional idea was sought. In both cases the chosen 87

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Figure 7.6: Capo di Ponte, Bedolina II Rock 7: particular of two topographic modules inserted into some p-forms of the rocky surface (untextured mesh view and hillshaded DEM in false colours).

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Figure 7.7: Grosotto (SO), Bedól sector D: photo (up) and tracing (below) of a sequence of topographic shield-shaped figures aligned on a grooved natural fracture.

A concise but brilliant solution to the question was proposed by geography historian Catherine Delano Smith in 1987:

have been “distorted” to fit the outlines of the rocks they were carved on and thus could not be “accurate” representations of some real layout. But this is to ignore the key property of topology, which is the preservation of contiguity but not shape, and to assess the prehistoric figures according to the then unformulated principles of Euclidean geometry (which stress the properties of

‘Not all modern archaeologists are willing to accept Bicknell’s interpretation of the “topographic figures”. A common objection is that many of these appear to 89

Angelo Martinotti, Alberto Marretta distance, direction and angle that preserve shape and underlie the modern concept of scale)’ (Delano Smith 1987, 67–68).

currents against the islands: an essential experiential datum for orientation in the Polynesian seas and understandable only to those familiar with navigation in the archipelago (Finney 1998, 475–485).

Delano Smith focused on the characters of “otherness”, based on topology and on a “non-mimetic” rendering of reality, of primitive mapmaking in contrast with the scientific and mathematical principles that characterise modern cartography. Essentially, it is a question of thinking of primitive maps in terms of schematic representations of a topological space as opposed to the commonly intended maps, conceived instead as analogical representations of a Euclidean space (Delano Smith 1982, 10–12).

An equally interesting case is that of the map drawn up by a chieftain of the Chickasaw nation, an indigenous people settled in the territories of present-day northern Mississippi and western Tennessee. The version come down to us, copied in 1723 from the original on deer skin by the will of Francis Nicholson, Governor of South Carolina from 1721 to 17258, represents, as the caption explains, ‘the Situation of the Several Nations of Indians between South Carolina and the Massisipi’ [sic]. The map reports, as a territorial element of reference, a summary and abstract scheme of the hydrographic network of the Mississippi, Ohio and Arkansas rivers, within which the various Indian nations are located, conventionally indicated with simple circles whose diameter is proportionate to the populousness and political importance of the communities (Figure 7.8c). The circles are connected to each other with straight lines that symbolise at the same time paths of communication, trade relations and alliances between the various tribes (Malcolm Lewis 1998, 99–101).

That primitive mapmaking was radically “other” from Western cartography is demonstrated by the scarce but significant ethnographic examples documented among modern tribal populations. In Africa among the Luba or Baluba people – an ethnolinguistic group indigenous of the south-central region of Congo that developed, between 1585 and 1889, a unified state called the Kingdom of Luba –, the elders Mbudye, a sort of secret cultural élite, were custodians of the complex historical traditions and religious and cultural knowledge of the Luba nation. They transmitted their initiatory knowledge through the lukasa, carved wooden tablets of rectangular shape with concave sides whose main face was adorned with a complex weave of engraved and embossed signs enriched by applied beads and buttons of coloured glass or other material (Figure 7.8a). These elements alluded to specific information relating to traditional contents, mnemonically learned, notably: events, facts, places, people linked to genealogies, lists and stories of kings, royal protocols and legends of ancestors’ migration. Travels of kings and paths of migration, the sacred traditions on springs and seats of protective spirits included spatial information related to the territory, encoded in an abstract and evocative form on these tablets. Some lukasas for certain tales and stories served as “mnemonic maps” helping to reconstruct and organise notions about the historical and sacred geography of communities into a coherent narration (Bassett 1998, 32–33).

It is a paradigmatic example of ephemeral mapmaking, consisting of sketches intended to accompany precise requests and specific oral descriptions. In the construction of these maps – inspired by a conceptual, mental image of the territory – references, components and information conveyed during the verbal exchange between sender and receiver came into play. Those informative elements, while remaining excluded from the representation, conditioned the figurative setting and representative choices of the map, constituting the background necessary for its full understanding. The reference grid consisted of a plot of morphological elements (landmarks) selected for easy recognition on the ground and for their common notoriety (mountain ranges, hydrography, coastline), generating the represented space and facilitating the placement of the details of interest. The metrics (distance and proportional relationships between elements) were purely indicative, the criteria and the representative conventions subjective and relative, conformed to knowledge, experiences, conceptions and traditional uses of its creator and his cultural context.

A similar example, in making use of an abstract and nonfigurative graphic language, are the so-called “nautical charts” used until the mid-nineteenth century by the indigenous inhabitants of the Marshall Islands during navigation in the archipelago. In the three types called mattang, meddo and rebbelib, they appear as complex flat lattices obtained by intersecting wooden strips of various lengths obtained from coconut fronds that represent the directions of ocean currents and flows and above all, according to conventional configurations, the modes of refraction of these against the islands of the archipelago. Some shells were applied to these strips, indicating the approximate position of the islands themselves (Figure 7.8b). In these maps, used by Polynesian fishermen and sailors, the main information conveyed concerned the modalities of refraction and reflection of waves and

Summarising the basic characteristics of primitive, preliterate and pre-scientific cartography, the following common traits can be identified: • the use of an empirical topological space, elevated to a conceptual principle and representative convention of schematic, essential and themed spatial representations, created to effectively communicate – without the constraints of the exact metric-proportional rendering – qualitative spatial information, relating to spatial  Preserved in the National Archives of London (the former Public Record Office). 8

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Figure 7.8: Examples of primitive mapmaking: A. Lukasa memory board, late 19th-early 20th century (photo: Brooklyn Museum, Creative Commons-BY); B. Marshall Islands nautical chart, Meddo type, 19th-20th century (Courtesy: Library of Congress, Geography and Map Division, Washington D.C.); C. manuscript copy of a original Chickasaw map on deer skin, 1723 AD. (London: Public Record Office; after Malcolm Lewis 1998).

relationships between selected elements of a territory. These representations are made in a representative language that can oscillate, with a variety of intermediate solutions, from a figurative-based syntax, including conventional but intuitive symbols, to a completely abstract structure, similar to a graph or diagram. In those maps the attention focuses on the accuracy and completeness of the qualitative spatial information, expressed visually in terms of order, reciprocal arrangement, sequence of territorial components, according to logics related to the information itself. • primitive and “informal” cartography is not created only to contain and transmit information of a spatial nature, but rather – and in some cases primarily – to evoke, or allude to a multiplicity of contents of various kinds, linked to places and territory, such as facts, events, institutions, traditions, legends, physical and “metaphysical” characteristics (transcendent presences, sacral connotations, spiritual qualities/ mana), experiential notions, territorial pertinences, hierarchical, political and/or kinship relationships between communities and social groups. The representation conforms to this need for expanded communication by adapting its form and structure in order to act as an ordering tool, an organiser of this heterogeneity of information. Its aim is to be the

intermediary of traditional contents of a narrative, sapiential and experiential nature. • the message and the interpretative keys are mainly entrusted to the oral communication channel, which operates in parallel and complementarity with the graphic-visual one expressed by the topographic representation. In a pre-literate cultural dimension, the background of knowledge related to a map – purposes, functions, representative conventions, contents, in a context of literate civilization commonly expressed by a textual apparatus (titles, legends, captions) – assume a capital importance in the construction and decoding of the cartographic tool itself. All those elements are drawn from the specific context that inspires the mapmaking, and from the experiences and the common knowledge shared by the author and the user. • what is depicted and how, the conventions and the representative symbols, the contents, the names, the concepts, the stories, the beliefs, the traditions linked to the places reproduced are orally passed on by the authors to the users, from the elderly to the new generations, from the shamans to other members of the community, from initiates to non-initiates. Those informations are learned mnemonically along with the instructions and techniques for reading those maps – devices created not to contain or convey information, 91

Angelo Martinotti, Alberto Marretta given as known, but to recall them according to orders and logical or narrative connections. The contents of these maps, the notions and skills to read them, not codified in the visual-iconic channel of the representation, but rather to the associated verbal one, therefore constitute a wealth of information external to the cartographic representation in its usual sense. The interruption of the oral tradition involves the virtually total, irreversible loss of this external informational component, essential for the understanding of the map, causing an “emptying” of the visual instrument, and consequently its illegibility – when not, at the limit, the unrecognizability of its cartographic nature.

Delano Smith, C. “The emergence of “maps” in European rock art: a prehistoric preoccupation with place”. Imago Mundi 34 (1982): 9–25. Delano Smith, C. “Cartography in the prehistoric period in the Old World: Europe, the Middle East, and North Africa”. In The History of Cartography, volume 1. Cartography in Prehistoric, Ancient, and Mediaeval Europe and the Mediterranean, edited by J.B. Harley and D. Woodward, 54–101. Chicago-London: The University of Chicago Press, 1987. Fedele, F.G. “Origini dell’ideologia cerimoniale centroalpina dell’età del Rame: una “fase zero” di IV millennio?”. In Il filo del tempo. Studi di preistoria e protostoria in onore di Raffaele Carlo de Marinis, (Notizie Archeologiche Bergomensi 19), edited by S. Casini, 77–100. Bergamo: Comune di Bergamo, Assessorato alla Cultura – Civico Museo Archeologico, 2011.

Only a systematic and exhaustive investigation of the complementary relationships between figuration and stone support, sustained by three-dimensional restitution techniques, can contribute to understand which of these general principles of primitive cartography, and in what way, informed the “topographic representations” of the Valcamonica-Valtellina prehistoric rock art.

Finney, B. “Nautical cartography and traditional navigation in Oceania”. In The History of Cartography, volume 2, book 3. Cartography in the Traditional African, American, Arctic, Australian and Pacific Societies, edited by D. Woodward and G. Malcolm Lewis (eds), 443–492. Chicago-London: The University of Chicago Press, 1998.

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Gavaldo, S. “Le raffigurazioni topografiche”. In L’arte rupestre del Pià d’Ort. La vicenda di un santuario preistorico alpino, (Archivi 10), edited by U. Sansoni, and S. Gavaldo, 162–168. Capo di Ponte: Edizioni del Centro, 1995.

Arcà, A. “Le raffigurazioni topografiche, colture e culture preistoriche nella prima fase dell’arte rupestre di Paspardo. Le più antiche testimonianze iconografiche nella storia dell’agricoltura e della topografia”. In La Castagna della Vallecamonica. Paspardo, arte rupestre e castanicoltura. Atti del Convegno Interdisciplinare (Paspardo, 6–8 ottobre 2006), edited by A.E. Fossati, 35–56. Paspardo: Comune di Paspardo, 2007.

Gavaldo, S. “Le rappresentazioni topografiche”. In Il segno minore. Arte rupestre e tradizione nella Bassa Valcamonica (Pisogne e Piancamuno), (Archivi 14), edited by U. Sansoni, A. Marretta, and S. Lentini, 137– 142. Capo di Ponte: Edizioni del Centro, 2001. Gavaldo, S. and Sansoni, U. “Le mappe delle origini. Considerazioni sulle prime raffigurazioni topografiche nel contesto tardo Neolitico-Calcolitico dell’area camuno-tellina”. Bollettino del Centro Camuno di Studi Preistorici 41 (2016): 47–70.

Arcà, A. “Naquane, Grande Roccia, dalla scoperta al modello bidimensionale immersivo”. Rivista di Scienze Preistoriche LXVI (2016): 253–293. Arcà, A., Casini, S., de Marinis, R.C. and Fossati, A. 2008. “Arte rupestre, metodi di documentazione: storia, problematiche e nuove prospettive”. Rivista di Scienze Preistoriche LVIII (2008): 351–384.

Huggett, R.J. Fundamental of Geomorphology (Third Edition). London-New York: Routledge, 2011.

Bassett, T.J. “Indigenous mapmaking in Intertropical Africa”. In The History of Cartography, volume 2, book 3. Cartography in the Traditional African, American, Arctic, Australian and Pacific Societies, edited by D. Woodward and G. Malcolm Lewis, 24–48. ChicagoLondon: The University of Chicago Press, 1998.

Malcolm Lewis, G. “Maps, mapmaking, and map use by Native North Americans”. In The History of Cartography, volume 2, book 3. Cartography in the Traditional African, American, Arctic, Australian and Pacific Societies, edited by D. Woodward and G. Malcolm Lewis, 51–182. Chicago-London: The University of Chicago Press, 1998.

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Martinotti, A. “Iconografia delle “rappresentazioni topografiche” in Valtellina tra Eneolitico ed età del Bronzo”. Bollettino del Centro Camuno di Studi Preistorici 35 (2009): 99–130. Martinotti, A. “Immaginario e ideologia nell’arte rupestre dell’età del Rame in Valtellina (Lombardia)”. Rivista di Scienze Preistoriche XLVIII (2018): 75–108. Medici, P. and Rossi, G. “Valcamonica 3.0: a new dimension in rock art recording. From tracing to Structure from Motion and Post-processing”. In Prospects for the Prehistoric Art research 50 years since the founding of Centro Camuno/Prospettive sulla ricerca dell’arte preistorica a 50 anni dalla fondazione del Centro Camuno, Proceedings of the XXVI Valcamonica Symposium (Capo di Ponte, 9–12 settembre 2015), edited by F. Troletti, 163–168. Capo di Ponte: Edizioni del Centro, 2015. Pace, D. Petroglifi di Grosio (Tellina Opuscula 2). Milano: Scuole Grafiche Pavoniane-Istituto Artigianelli, 1972. Pace, D. “Preminenti aspetti petroglifici nel promontorio grosino di Giroldo”. Sibrium XVI (1982): 39–50. Priuli, A. La cultura figurativa preistorica e di tradizione in Italia (volume 1). Pesaro: Giotto Printer, 1991. Rondini, P. “Dos dell’Arca (Capo di Ponte, BS). La ripresa dello studio, cinquant’anni dopo”. In Digging up excavations. Processi di ricontestualizzazione di “vecchi” scavi archeologici: esperienze, problemi, prospettive, Atti del Seminario (Pavia, 15–16 gennaio 2015), edited by P. Rondini and L. Zamboni, 155–166. Roma: Edizioni Quasar, 2016. Rondini, P. “Digital rocks. An integrated approach to rock art recording: the case study of Ossimo-Pat (Valle Camonica), monolith 23”. Archeologia e Calcolatori 29 (2018): 259–278. Rondini, P. and Marretta, A. 2019. “Il sito protostorico di Dos dell’Arca (BS): la campagna di scavo e documentazione 2018 dell’Università di Pavia (progetto Quattro Dossi – fase II)”. FOLD&R Fasti On Line Documents & Research 444, (2019): 1–38 [http:// 93

8 New digital insights over the Domus de Janas with paintings: some case studies Giuseppa Tanda, Carla Mannu Abstract There are 3,500 funeral hypogea that have been counted so far, called “Domus de Janas” and ascribed to the Middle Neolithic B, Late Neolithic and Copper Age (end of 5th to the 3rd millennium BC), around 150 of these still have visible traces of paintings. This chapter highlights the problems concerning the techniques, pigments and tools used, the figurative motifs and their typology, the techniques of documentation, their territorial diffusion and their inclusion in the chrono-cultural sequences of Sardinian Prehistory, and in the wider sphere of Mediterranean Prehistory. Specific attention is made regarding the most recent techniques used for documenting the representations: the use of the application ‘open-source DStretch’, with the ‘albedo’ image (the pure surface colour, without any influence of projected colour shades), drawn from the 3D processing of the surface’s dataset using the Photometric Stereo technique. Within this frame of reference is presented the recent research conducted on the Pubusattile IV. Keywords Domus de Janas – Painting – DStretch – Photometric stereo 8.1 Preface

janas were recognised as socially shared funeral models, perhaps a territorial mark of the communities. Tombs are often stand-alone or arranged as necropolises (from 6 to 39 tombs: Contu 2000, fig. 4); sometimes – but in small numbers – they are connected to the adjacent residential settlements. Known since the 19th century, Giovanni Lilliu (1967, 105-125; 2011, 229-254) and Ercole Contu (1997, 115-156; 2000, 313-366) summarised the general problems of reconstructing their origin, development, chronology and rituals. Recently, these general frameworks have been supplemented, clarified and, at times modified (Tanda 2015a; 2015b; 2017).

There are approximately 3,500 prehistoric chamber tombs in Sardinia, artificial caves for funerary and collective use, commonly known as domus de janas, scattered throughout the island, mostly in central-western Sardinia, with sporadic presence in Gallura. This distribution may be explained by the presence of lithotypes suitable for excavation (such as ignimbrites and limestones), that communities settled in the surrounding area from the end of the 5th to the 3rd millennium BC, and that the domus de

Currently, the domus de janas is considered as the direct result of the Middle Neolithic funerary hypogeism, due to the major structural analogies with the hypogea of the Cuccuru S’Arriu-Cabras necropolis, attributed to the Middle Neolithic I (5th millennium: 4800 ± 4300 BC). A careful reflection on the data in the bibliography has allowed new clarifications of the genetic problems and the development of the funerary model of the domus de janas, as well as of its chronology (Tanda 2015a; 2020a, 246-250). Therefore, plausibly the hypothesis that funerary hypogeism, which began in the Bonuighinu culture continued uninterrupted in subsequent cultures, San Ciriaco, Ozieri I and II, through to the Bronze Age. In parallel with similar trends found in the general Neolithic lines, from the ancient to the final phase, as is testified by the diagnostic findings. As for the chronology, the radiometric analysis carried out on the coal samples from the domus de janas IV of Molia-Illorai have expanded the chronological scope of excavation and the use of the hypogeum (Tanda 2015a, 352). Dated to between the 4230 ± 3820 BC, thus or the5th millennium BC, or Middle Neolithic II, the time when the San Ciriaco’s culture developed and the period in which the figurines and ceramic finds are dated to (Tanda 2020a, 248-249; 2020b). 95

Giuseppa Tanda, Carla Mannu 8.2 The painted Domus de Janas

presence in the secondary cell is rare. The autopsy analysis of the characteristics of the pictorial traces leads to the identification of some paint application trends: 1) the prevailing even, monochrome and red colouring; 2) polychrome, with various shades of red, black/dark grey, white/ivory and yellow. The polychrome is reported in 14 domus de janas, i.e., in Benetutti-Molimentos (red, grey), Fonni-Gariunele I-II,VIII (red and yellow) and Su Nodu ‘e Serramene (red, yellow), Illorai-Molia I (red, grey) and VII (various shades of red and grey), Putifigari-S’Incantu (red, grey), Villaperuccio-Montessu X, Sedilo-Lochele 1 (red, grey, yellow), Lochele 2 (red, white ) and Ispiluncas II (red, grey, yellow), Thiesi-Mandra Antine III (red, grey, ivory), Villanova Monteleone-Pubusattile IV (white, grey and red): Tanda 1985, 32, 62, figs. 30 a, b; 2015a, 186, 189; 1992a; Falconi 2018, 63.

Among the 3,500 known domus de janas, 215 of them, accounting for 6.2%, display artistic motifs, made using different techniques: sculpture in 120 hypogea, painting in 112 of them, engravings in as few as 54 tombs (1.5%), applications of clay laths in 1 domus de janas. Techniques are often used in combination, as specified in Table 8.1. Painted tombs are rich and varied, increasing in number due to the re-examinations of previously surveyed hypogea by archaeologists and / or enthusiasts, and to the use of more powerful lighting devices and improved software used to identify and document findings. The devices and software such as DStretch allow the detection of traces of colour or remnants of hardly distinguishable or, in some cases, invisible figurative motifs.

In general, or, in at least 8 cases, the colour appears to be applied directly on the rock, on the plaster, e.g., in the hypogea of Bonorva-Sa Pala Larga VII, Illorai- Molia I and VII, Nughedu Santa Vittoria-Sas Arzolas de Goi I and II, Sedilo, Ispiluncas II and Lochele I and VI. Pigments are both inorganic and organic, as demonstrated by the analyses performed to date to determine the pictorial components and the methods of painting. In 1981 (Cariati et al. 1981, 291-300), a sample of red painted plaster from the domus de janas I in Molia-Illorai was analysed in order to identify its composition. The mineralogical investigation carried out on the thin sections of the sample revealed two mixtures under the red pigment: the first showed a fine matrix; the second showed a coarse matrix, adhering to the rock, classified as rhyolitic or rhyodacitic tuff. The layers of plaster are likely to be the result of the grinding and transformation of tuffaceous rock similar to the one below. Five instrumental techniques were implemented for the chemical analysis: spectrographic, thermogravimetric and differential thermal analysis, x-ray diffraction (XRD) and infrared spectroscopy. Based on the results obtained, it was possible to establish that the two layers of plaster were made of the same material and that no lime was used as a binder. Furthermore, the red pigment consists of iron oxides and silicates, commonly known as “red ochre”. In 2002 and 2003 (Rampazzi et al. 2002, 237-240; Tanda et al. 2003, 61-71), 5 samples from the necropolis of Anela-Sos Furrighesos were analysed to verify the nature and origin of the pigments used to as paint, as well as the pictorial technique and its distribution in Sardinia.

8.2.1 Morphological and planimetric typology The painted tombs fit into the various lines of the landscape, characterising it historically, and manifesting themselves according to a morphological typology. These are divided into eight categories recognized so far within the decorated domus de janas namely: 1) Subflat; 2) Outcrop; 3) Light slope; 4) Steep slope; 5) Hill; 6) Mountainside; 7) Spike; 8) Boulder Isolate (Tanda 2015a, 58). In some rare cases, for example in Anela-Sos Furrighesos, the reference residential settlement has been identified. Unfortunately, to date, conducting verification tests in order to establish their functions and chronology has not been possible. The plans are diverse, from simple to complex, gradually increasing up to 16 rooms, as the domus de janas VII of Molia, based in Illorai, shows. The complexity of the iconographies does not match a preset design, a sort of preordained design idea, but it is the result of renovations and additions having been carried out over the millennia when the hypogea were used. The long period of use of the tombs highlights their identity and political value, linked to the social organisation of the communities and the importance of the elites ruling over the territorial system. 8.2.2 Pigments and trends The artistic motifs are mostly found within the ante­ chamber or pavilion and the next or main cell. Their

Table 8.1: The artistic motifs of the domus de janas: data by tombs and techniques. Techniques

Sculpture

Painting

Engraving

Sculpture

71

31

18

Painting

31

63

17

Engraving

18

17

18

1

1

1

112

54

1

Plastic application Total

120

96

Plastic application

New digital insights over the Domus de Janas with paintings To determine the nature of colours, different analytical techniques were implemented: X-Ray Diffraction (XRD) and Scanning Electron Microscopy coupled with Energy Dispersion X-Ray Spectrometry (SEM-EDX), while the nature of organic substances was investigated through Gas Chromatography coupled to Mass Spectrometry (GC-MS). The red pigment was identified as hematite (SEM-EDX and XRD), while in 3 out of 5 samples (tombs II and XV), GC-MS analyses showed the presence of egg.

The chessboard can be seen in two tombs only: in Villanova Monteleone-Pubusattile IV, painted red on the side walls of the antechamber and in Bonorva-Sa Pala Larga VII, in black, on the ceiling (Tanda 1992a; Usai et al. 2011). The roof appears in three tombs: in Thiesi-Mandra Antine III, Ardauli-Mandras / Mrangias and Pubusattile IV; the trellis, the cane wall, the open gallery in three hypogea, in Ardauli-Mandras / Mrangias, in Buddusò-Ludurru I and in Nughedu Santa Vittoria-Sas Arzolas de Goi II (Tanda 1992b), respectively. The protome is reported in AnelaSos Furrighesos VI, Mandra Antine III, in Bessude-Enas de Cannuia IV (Tanda 1984, fig 22; 2015 a, 191,1; 199,1; Contu 1964b, 233-263) and in Pimentel- S’Acqua Salida (Tanda 2015b, Tav. Concl. III); the spiral in Mandra Antine III and Bonorva-Sa Pala Larga VII. The band is present in Sos Furrighesos VI and Villanova Monteleone-Pubusattile IV. The hourglass is reported in Mandra Antine III, the row of triangles in Busachi-Campumaiore XII.

The inorganic substances used include hematite and the earthy variety of ochre, for red, ivory and yellow; in manganese oxide for dark grey. The only organic substance identified is the coal from which the grey is obtained. In 2007 (Rampazzi et al. 2007, 559-569) the results of the analyses on pigment samples from 8 other domus de janas were published: the hypogea of Thiesi-Mandra Antine II (red and black / dark grey samples), Illorai-Molia VII (red), Bonorva-Sant’Andrea Priu, Tomba del Capo (red and black / dark grey), Sedilo-Binzales 2 (black / dark grey), Sedilo-Imirmichis (black / dark grey), SediloIscannitzu (red), Sedilo-Su Littu 1 (red and black / dark grey), Pimentel-Corongiu (red). The analyses confirmed the use of hematite for red, carbon for black / dark grey and egg as a binder. The organic substance has been identified in 6 tombs (Mandra Antine II (red and black), Molia VII (red), Sant’Andrea Priu SAp37 (red), Binzales 2 (red), Su Littu 1 (black) and Corongiu (red). In Corongiu, traces of coniferous resin have also been documented, perhaps used for conservation or aesthetic reasons.

The remaining 8 motifs appear only in Mandra Antine III, which, overall, includes 10 figures out of the 17 listed. These motifs are also performed with different techniques and are sometimes present on the external surface of ceramic containers, presenting a repetitive character and therefore assuming a cultural and chronological meaning. For example, the spiral, in the recurrent painted form of Sa Pala Larga 7 (Usai 2020, 317-319, no. 344-346), is also reported in the engraving in Bonorva – Sa Pala Larga 3 (Tanda 2015a, 290); in the simple form of Mandra Antine III, it appears on the ceramic fragments of the San Ciriaco culture, in Cuccuru S’Arriu-Cabras (Santoni 2012, 118, fig. 4, f) and Fig. 8, h) and the Ozieri culture, e.g. in MogoroPuisteris (Tanda 1983; Atzeni 2005, fig. 6,4, 128); the painted hourglass by Mandra Antine III appears, sculpted, in Ossi-Tomba delle Clessidre (Tanda 2015 a, 178, 2; fig. IX. 1-2), engraved in Bortigiadas-Tisiennari (Tanda 1977b; 2015 a, Fig. I .8: 1) and on pottery from Illorai-Molia I of the Ozieri I culture (I half of the IV millennium BC) (Tanda 2015 a, Fig. IX.3, 3). The chessboard is present in Cagliari-Grotta del Bagno Penale, on an earthenware olla pot of Bonuighinu culture (2nd half of the 5th millennium BC; Tanda 2015 a, 357.9); the protome of S’Acqua Salida can be traced back to the sculpted motif of MamoiadaIstevene (Tanda 2015 a, 299, Fig. VIII. 1, 1).

8.2.3 How is the colour laid? Traces of mostly red colour can be observed on the walls, ceiling and floor of 91 hypogea (Tanda 2003). In only one case, at present, in Illorai-Molia VII, it is arranged on distinct horizontal and parallel bands, with different shades, from bright red to pink. The even colour, monochrome and red, is found on protomes or on horns or on bands simulating horns and merged with false door, carved in relief or false relief in 17 tombs, e.g., in Anela-Sos Furrighesos II and VI and Bortigiadas-Tisiennari (Tanda 1985, Figs. 31a and b, Fig. 20; 2015 a, 191 203 and 204), Bonorva-Sa Pala Larga VII (Usai et al. 2011), Chiaramonti-Su Murrone I and Mandra Antine III-Thiesi (Tanda 1985, 141, 150). In 19 domus de janas the colouring appears on architectural motifs such as architraves or door frames, false doors, double sloping ceilings represented with central beam and lateral joists, with single sloping or semicircle as, for example, in the XII and XV tombs of Anela-Sos Furrighesos), at Monte Siseri I or S’Incantu-Putifigari, Nughedu Santa Vittoria-S’Angrone: Tanda 2015 a, 199, 186, 207).

In two cases, in Bortigiadas-Tisiennari and in PimentelCorongiu (Tanda 1985, 183-187; Lilliu 2011, 248-249), a red thread frames the incisions and, in one case, i.e., in Tisiennari, also the carved horn-shaped motif that is found on top of the carved and painted false door (Tanda 1977b). Speaking of techno-morphological typology, in the sculpted motifs we recognized two styles, the Curvilinear and the Rectilinear styles, already highlighted in 1977 (Tanda 1977, 13 et seq.).

In 11 tombs, all figurative motifs display a schematic pattern and appear painted in red or, rarely, in black / dark grey and light yellow. They are distinct on the formal level: the arc, the circle, the semicircle, the hourglass, the rectangle, the spiral, the protome, the row of triangles, the simple or double oblique band, the zigzag bundle, the chessboard, the trellis, the cane wall, the roof, the band, the open gallery.

Furthermore, we can see the figurative evolution process that has been defined for some time (Tanda 2015a, 284, Figs. VIII.14,1) which begins with the simple schematic motifs, passes through the transition ones and ends with 97

Giuseppa Tanda, Carla Mannu Methodology

the complex motifs. The simple schemes are those that preserve the distinctive anatomical features of the animal represented (Anela-Sos Furrighesos VI). In the motifs in which the corniform motif is architecturally fused with the door (e.g., in Villanova Monteleone-Calarighes II), that is, in the transition motifs, the symbolization of the door itself is documented, which assumes the place and meaning of the animal’s head. The motif, thus changed, is created on the back wall of the next cell, which is the main one (Alghero-Tanca Calvia I: Tanda 2015a, 199), assuming the name of the complex scheme.

8.3.1 Processing and study of paintings with DStretch The painted pictures in the domus de janas are acquired by shooting pictures using a DSLR, in RAW format, and analysed by DStretch, a plug-in of the image processing software “ImageJ” (Harman 2005), that increases the contrast of red and yellow hues, to detect the details that are invisibles with the naked eye plainly. This script processes a colour space decorrelation with a 3x3 covariance matrix, which multiplies the original image colour to create a new false-colour picture. The most suitable colour spaces for the domus de janas rock art paintings analysis is the LDS and LRE filters. In wider terms, the LRE is more suitable to highlight red colour shades. LDS works better with yellows, but in a few cases, it also works well with reds. The output is a false colour image where the traces of paintings are highlighted, including the kind of traces which are clearly invisibles. However, ImageJ underlines any red element in the picture, both paintings and rock oxidation.

The colour emphasises the sculpted motif, and, at the same time, it increases its value and effect because it is red, that is, the colour of blood and regeneration. Likewise, the presence of colour on architectural motifs refer to two values: aesthetics and cult. The architectural motifs are the imitation of the details of a house, sometimes also represented in the plan. Unfortunately, the huts used by the living communities is unknown, except for the houses of the settlement of Serra Linta in Sedilo (Tanda 1998a, 86-90; 2015a, 158-160) where there is a planimetric scheme consisting of a semicircular space followed by a rectangular one, reported in several domus de janas that show traces of paint such as, the hypogea of Alghero -Santu Pedru I or Tomba dei Vasi Tetrapodi (Contu 1964a) and Cuglieri-Sa Spelunca de Nonna (Santoni 1976, 45, fig. 7). Unfortunately, the village has not yet been excavated, so there is a lack of essential information to reconstruct its elevation and roofs and to unequivocally identify its functions, meaning and absolute chronology. The lack of data is partly overcome by the results of the study on hypogeal architecture, which allowed not only to make a hypothesis of hut reconstruction (Tanda 2015a, 158-160) and to identify another eight modules corresponding to as many houses, of which, however, we have no archaeological evidence, but also to point out the characteristics of the ceiling representations, framed in a typology divided into six types (Tanda 2015a, 126-163) and other architectural details such as pillars, columns , pilasters, counters, tables. In this regard it is noted that significant examples of extraordinary architectural value are known, for example, in addition to those mentioned above, the tombs of Putifigari-Monte Siseri and Sassari-Li Curuneddi VI (Tanda 2015a, 322-323). In Nughedu Santa Vittoria-Sas Arzolas de goi II, an open gallery is painted on the wall. The walls were built using canes, as suggested by the vertical and parallel motifs painted on the back wall of BuddusòLudurru I and in some cases, using half-timbering, as in Ardauli-Mrangias, one of the case studies described below.

The DStretch plug-in was used for the first time in Sardinia on domus de janas by Deligia, Fernández Ruiz and Spanedda (Deligia, Fernández Ruiz, Spanedda 2014, 157-174), and then by other researchers. Even now it is used in some other hypogea on the island. 8.3.2 Case studies In this work, the ImageJ software is used on the Tomba IV, Pubusattile necropolis, Villanova Monteleone, and on the Tomba di Mrandas, Ardauli. Tomba IV, Pubusattile necropolis, Villanova Monteleone The domus de janas IV of Pubusattile belongs to a necropolis excavated in a trachyte crag, currently surrounded by woods. This tomb has an entry panel 2 metres above ground level, accessed by stairs carved in the rock, which are currently mostly not visible, possibly destroyed. The entrance opens onto an antechamber and is followed by a main chamber, divided into three parts by a balcony in the east area and a partition in the west area. Both of the chambers contain a large number of red and white paintings (Figure 8.1). The DStretch processing applied to the pictures taken in the antechamber allowed us to confirm already published materials and to have a clearer idea about the painting subject found on the west wall. Despite being mostly deteriorated by atmospheric agents, that latter affecting this wall more than the opposite one, the wall displays red zigzag vertical bands on the left and a red and white chessboard on the right. This representation is symmetrical to the one painted on the opposite wall (Figure 8.2), as already published (Tanda 1992a, 479-493).

8.3 Case Studies In this text we have declared that traces of colour or remains of paintings, even if they are not visible, are found in many domus de janas (even 91 hypogea). It was an opportunity for testing the usefulness of the ImageJ software to detect and check these kinds of traces.

From an accurate analysis of the chamber, a unique motif was reported on the ceiling (Figure 8.3), yet to be interpreted. 98

New digital insights over the Domus de Janas with paintings

a.

Figure 8.1: Planimetry of Pubusattile IV, Villanova Monteleone (SS) (from Tanda, 1992).

Tomba di Mrandas, Ardauli b.

The Mrandas domus de janas was excavated on a trachyte outcrop, currently surrounded by Mediterranean maquis. The same outcrop also showed an excavation attempt of another domus de janas. Mrandas is a tomb consisting of multiple chambers (Figure 8.4) with a complex longitudinal planimetry, including a small atrium, which shows clear red ochre painted representations of village’s huts. These village huts were never found, because of the perishability of the materials used to build them, such as timber or canes, but they have largely been studied based on other rock art representations (Tanda 2015c, 119-208).

Figure 8.2: A: Survey of the west wall of the antechamber. B: Survey of the east wall.

connecting the main cell and the antechamber (Figure 8.6). Additional similar trellis has now been discovered, using DStretch, on the walls of the secondary cells (Figure 8.7). 8.4 Discussion 8.4.1 Why are the homes of the living fully or partially represented in hundreds of domus de janas?

The new techniques allowed new discoveries about the painted motifs. In addition to the red colour of the antechamber floor that was likely to be plastered and portrayed a hearth in the centre, and the ceiling with the motif of a circular band with three red beams on each side something new was found painted in the main and secondary chambers, but not yet recognizable.

An answer comes from the funerary ideology of the Neolithic and Copper Age communities of the late 5th to 3rd millennium BC, based on the belief in an otherworldly world, the final destination of the dead. After death, the deceased, who in life were part of the elites, were placed in a tomb that mimicked the living quarters. The bodies were surrounded by everyday objects, in the belief that they could also be useful in the afterlife, including furnishings, such as carpets, represented at Pubusattile IV. The ritual actions performed during and after the burial aimed at favouring and accelerating the passage into the afterworld. However, the house might represent a special house, purposely built to host the deceased. While the rituals were performed, as documented on an ethnological level in Indonesian populations also consisted of the sacrifice of bovine animals, the heads of which were then displayed on the façade, to show the high rank they held and the economic power exercised by the family. This hypothesis, however, has had no reliable archaeological evidence to date (Tanda 2000, 405-406; 2015a, 274, 349; 2015b,

As already documented (Loi 2006, 153-160), the main cell ceiling has a roof representation. To the naked eye, a preliminary analysis demonstrated “a one-sloped or saddle roof with short rounded sides portrayed with four red bands, three of which stem from a semi-circular element”. A more accurate analysis performed using DStretch, despite the poor conditions of the paintings, suggests the existence of a saddle roof with a central beam and at least five or six beams symmetrically arranged around it, reminiscent of the lateral beams of a roof (Figure 8.5). Another analysis of the domus de janas shows a trellis on the walls of the main chamber, as already published and another geometrical trellis-like motif over the panel 99

Giuseppa Tanda, Carla Mannu

Figure 8.3: Survey of the ceiling of the antechamber.

Figure 8.5: A: False color image after d-stretch processing of the south-east part of the main chamber ceiling of Mrandas. B: Survey.

Figure 8.4: Planimetry of Mrandas, Ardauli (OR) (from Loi, 2016).

100

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Figure 8.6: False color image, with desaturation, of the main chamber wall over the opening.

323). In eight hypogea, the colour is applied to the plaster. The presence of the plaster is explained primarily by the need to reinforce rocky surfaces, mostly ignimbrite, very degraded, such as the tuff where the domus de janas of Illorai-Molia were excavated in. However, the need to decorate rough surfaces is not excluded. In many cases red has a religious value, being the colour of the blood and a symbol of life.

and, in some cases (Sos Furrighesos XV), showed finds from the Ozieri culture. The same culture is witnessed in other hypogea, such as Alghero-Anghelu Ruju XIX and XXVIII, Anela-Sos Furrighesos XII, Ossi-Littoslongos and Ossi-Tomba delle finestrelle. The similarities between magical-ritual figurations present on the wall surfaces of the hypogea and figurative motifs made on ceramic finds lead to a similar chronological framework (Tanda 2015a, 357, Fig. IX.4. N. 9; Santoni 2012, 121 -134; Atzeni 1978, 128, fig. 6, 4): the simple spiral is attributable to the culture of San Ciriaco (Cabras-Cuccuru S’Arriu) and to Ozieri I (for example to Mogoro-Puisteris); the recurrent spiral, documented in the hypogeum VII of Bonorva-SaPala Larga shows analogies with motifs engraved in Malta in the temple of Tarxien, and painted in the hypogeum of Hal Saflieni, but the Sardinian chronology differs slightly from the Maltese one. Hal Saflieni, dating back to the second half of the 4th millennium BC (BCE 3300-3000) is therefore compatible with Ozieri II; Tarxien dates back to the mid3rd millennium BC (BCE 3000-2500), the Copper Age (Evans 1982; Bonanno 2020, 46). Even the domus de janas of Sa Pala Larga 7 showed materials from the Ozieri culture still under study.

8.4.2 When were the figurative motifs painted? There are a number of different diagnostic supporting elements (Tanda 2015a, 351-361), which primarily refer to the painting tomb morphologies. Type 5, is an imitation of the houses of Serra Linta, reported at the domus de janas I and IV of Molia, was dated by radiometric analyses obtained on samples taken during the stratigraphic excavation: the oldest was compatible with the San Ciriaco culture (4230 3820 BC); the most recent was compatible with the Ozieri I (1st half of the 4th millennium: for example, 3970 - 3700 BC) and Ozieri II (between the 1st and 2nd half of the 4th millennium: for example, 3640 - 3370 BC) culture. As for the materials found during the excavations, the in-depth and on-going study of the two archaeological contexts will hopefully lead to the clarification of the chronological classifications of all the finds. The Tomb of the Tetrapod Vessels, Santu Pedru I-Alghero, refers to Type 5, where materials from the Ozieri I culture were discovered. Type 4, including “T” tombs, as reported in the painted tombs

As for the sculpted and painted protomes, they are all expressions of Bucranium 1 (horns upwards), dating back to the same period, at the current state of research, that is, 101

Giuseppa Tanda, Carla Mannu final results: Tanda 2015a, 360), bearing in mind its peculiarities, including the variety of techniques of execution, but within the cultural context of which hypogean art appears to be a significant expression. The results of the studies highlighted so far have revealed some characterising factors: tendency to repeat motifs, to modify them, to disaggregate them, and sometimes developing figurative schemes such as complex motifs which, in some cases, would be unintelligible individually without keeping in mind their entirety. Therefore, exploring a diverse set of lines “would fail to explain the full phenomenon and the cultural reference framework – in time and space – resulting in partial and idiosyncratic perceptions, devoid of the ideological connective tissue, therefore quite irrelevant and useless to identifying their meaning” (Tanda 2015a, 360). Consequently, it seems essential to briefly describe the reference cultural framework and, more specifically, some components thereof, such as the economy and social organisation. The few, heterogeneous and incomplete data available on the economy, coming from paleo-ethnological and ecological sources, suggest a subsistence economy based on agriculture and livestock (Zedda 2015; Ucchesu 2015), integrated by crafts with the production of tools and containers of daily use and textile articles (clothes and carpets) and, integrated by fishing, hunting, gathering, procurement, processing and exchange of obsidian and, perhaps, flint. The analysis of the paleo-ethnological data reveals signs of a structured social articulation, which can be classified, moreover, as signs of social inequality. These signs are made up of the plans of the domus de janas which, at times, develop in a complex way, enriching themselves gradually, up to 16 rooms over the long period of restructuring and use of the hypogea, as for instance the domus de janas VII of Illorai-Molia shows. Other signs can be recognized in the sculpted, engraved or painted figures on the walls of a small number of tombs, just 112 out of the 3,500 registered and in the represen­ tations of architectural elements, documented throughout Sardinia. The presence of figurative signs highlighted in only a few hundred domus de janas, the absence in the others could be the expression of a hierarchical society (Tanda 2015b, 322-323). However, this society is not proved by the archaeological materials of its funerary assemblage, at the current state of research. As well as, the overall reconstruction of the social structure is described as tribal, showing an organisation and differentiation of activities, as already stated, where elites, groups/classes suggest the identification of either exclusive or prevalent patrons commissioning tombs with the expressions of art (Tanda 2015a, 359-360; 2015b, 318325).

Figure 8.7: A: Picture of the front wall of the secondary chamber. B: False color image after d-stretch processing. C: Survey.

Ozieri culture 1 (1st half of the 4th millennium) and 2 (2nd half of the 4th millennium) for simple schemes (8 motifs); end IV-Beginning of III the transition schemes (3 motifs); end IV-Beginning of the III complex schemes (3 cases of study). Of great importance are the painted protomes of Pimentel-S’Acqua Salida which are part of Bucranium 2 (horns downwards). 8.4.3 Why did the Neolithic and Copper Age communities mainly paint their tombs red, in the variety of expressions described above? What was the underlying meaning?

Regarding the function of the representations, the following hypotheses are likely to be true: 1) they could be signs performed on the occasion of the celebration of events such as death/funeral, the rearrangement of the hypogeum,

In addressing the topic of meaning, it appears fundamental to conduct the analysis on the entire hypogean artistic phenomenon in its development (origin, development, 102

New digital insights over the Domus de Janas with paintings

Figure 8.8: Survey of back of the cell of Pubusattile IV, Villanova Monteleone.

the foundation rite, repetitive ceremonies/anniversaries, etc.; 2) they could be representations of furniture elements of a particular hut, perhaps built specifically as a place for funerary ritual ceremonies, imitated in the domus de janas.

of the passage rituals (Tanda 2000, 405-406; 2015a, 274; 2015b, 324). One problem remains unsolved: the ideological relationship between the painted motifs and ritual animal sacrifices depicted on the walls of the domus de janas. The killing of oxen as ritual sacrifices does not invalidate this interpretation but confirms what is already present in literature. The fundamental element of a ritual is the choice to sacrifice specific animal species and not others, because it is functional to the system. The representation in the rock would fix the events of the elites for future reference and as a sign of identity carved on a tomb where the members of the group, the ancestors, are buried, with whom the living communicate through flower or food offerings. Regardless of the details of the interpretative problem, however, it is emphasised that the overall picture of the art of the domus de janas has revealed some characterising factors, including repetition. Repetitiveness is the fundamental element of the ritual, that is expressed within the funerary ideology of the recent Neolithic Age and the Copper Age, and it relates to the relative aspects of spirituality and religiosity.

8.4.4 What are the reasons? From a semiotic point of view, figurative signs/motifs are the signifiers, which lead to the meanings and, therefore, to the contents. The signifier identified in the Bucranium 1 (prevailing sign) is the ox that meets various needs, relevant on the existential level (e.g., nutrition, transport, fertilisation), and functions as an integral part of the funeral ritual underlying the domus de janas. Therefore, the meanings of the symbol, which has multifunctional contours are wealth, strength, fertility and transport. Its representation in the domus de janas acquires a ritual value, also becoming propitiatory: the symbol ensures the wealth, strength and fecundity, that is, the continuity of the group, threatened by death. With the execution of the symbol, therefore, the existential system crisis caused by death is resolved. At the same time, the transport is concluded, i.e., the passage of the deceased into the afterlife. The ox is also a means of transport. When a man is still alive, the animal can carry men, animals and goods; when a man dies, the animal symbol executed on the walls of the tomb facilitates or marks the passage of the deceased to another dimension. It is, therefore, a tangible display

In the case under study, this occurs within the life-deathrebirth cycle, that is based on the mythical prefiguration of a male principle and a female principle, modelled on the cycle of nature, rooted in the food producing classes, that is, the farmers and the herders, perhaps “the patrons of the decorated domus de janas” (Tanda 2015b, 325). 103

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Tanda, G. “Arte e Religione in Sardegna. Rapporti fra i dati monumentali e gli elementi della cultura materiale (Nota preliminare)”. In Valcamonica Symposium ‘79, The Intellectual Expressions of Prehistoric Man: Arte and Religion, edited by AA.VV, 261-279, Milano. CoEditori, Capo di Ponte: Edizioni del Centro, Milano: Jaca Book Spa, 1983.

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Deligia, G.G, Fernández Ruiz, M. and Spanedda, L. “La decorazione dell’ingresso della domus de janas di Perdonigheddu (Sorgono, NU): applicazione dell’estensione Dstretch del software ImageJ”. Archeologia e Calcolatori 25 (2014): 157-174.

Tanda, G. “L’Arte del Neolitico e dell’età del Rame in Sardegna. Nuovi dati e recenti acquisizioni”. In Istituto Italiano di Preistoria e Protostoria, Atti della XXVIII Riunione Scientifica dell’Istituto Italiano di Preistoria e Protostoria, in memoria di Paolo Graziosi: L’arte dal paleolitico all’età del bronzo, Firenze 20-22 novembre 1989, 479-493. Firenze, 1992a.

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Tanda, G. “La tomba n. 2 di Sas Arzolas de Goi a Nughedu S.Vittoria (Oristano)”. In Sardinia Antiqua. Studi in onore di Piero Meloni in occasione del suo settantesimo compleanno, edited by P. Meloni, E. Atzeni, L.M. Bonello, 75-95. Cagliari: Edizione Della Torre, 1992b.

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Loi, C. “Ardauli (Sardegna, Italia). Domus de Janas Dipinta di Mandras”. Arqueología y Territorio 3 (2006): 153-160. Rampazzi, L., Cariati, F., Tanda, G. and Colombini, M. P. “Characterization of wall paintings in the Sos Furrighesos necropolis (Anela, Italy)”. Journal of Cultural Heritage 3 (2002): 237-240. 104

New digital insights over the Domus de Janas with paintings Tanda, G. “L’ipogeismo in Sardegna arte, simbologia, religione”. In Università degli Studi di Sassari, Atti del Congresso Internazionale L’ipogeismo nel Mediterraneo, Sassari-Oristano, 23-28 maggio 1994, Volumi I-II, Sassari, 399-425. Sassari: Università degli studi di Sassari, Facoltà di Lettere e filosofia, Istituto di Antichità, arte e discipline etno demologiche e Dipartimento di Scienze umanistiche e dell’antichità, 2000. Tanda, G., Cariati, G., Colombini, M. P. and Rampazzi F. “Caratterizzazione delle pitture parietali presenti nella necropoli di Sos Furrighesos (Anela-SS)”. In Studi in onore di Ercole Contu, edited by AA.VV., 61-81. Sassari: Editrice Democratica Sarda, 2003. Tanda, G. “L’uso del colore nella Preistoria della Sardegna”. In Atti della XXXV Riunione Scientifica Le comunità della Preistoria italiana. Studi e ricerche sul Neolitico e l’età dei metalli. In memoria di Luigi Bernabò Brea, 2-7 giugno 2000, Firenze, 465-482. Firenze: Istituto italiano di preistoria e protostoria, 2003. Tanda, G. Le domus de janas decorate con motivi scolpiti. Vol. I. Cagliari: Condaghes, 2015a. Tanda, G. (a cura di). Nuove tecniche di documentazione e di analisi per una ricostruzione delle società dalla fine del V al III millennio a. C., Volume II. Cagliari: Condaghes, 2015b. Tanda, G. “Dalla preistoria alla storia”. In Storia della Sardegna. Dalla preistoria ad oggi, edited by M. Brigaglia (a cura di), 25-92. Cagliari: Edizioni Della Torre, 2017. Tanda G. “Le domus de janas”. In La Preistoria in Sardegna, Il tempo delle comunità umane dal X al II millennio a. C., edited by T. Cossu, C. Lugliè (a cura di), 244-263. Nuoro: Ilisso Edizioni, 2020a. Tanda, G. Corpus delle domus de janas decorate, voll. I-III, (in corso di completamento), 2020b. Ucchesu, M. “L’agricoltura preistorica in Sardegna tra il V e il III millennio a. C”. In Nuove tecniche di documentazione e di analisi per una ricostruzione delle società dalla fine del V al III millennio a. C., Volume II, edited by G. Tanda (a cura di), 103-114. Cagliari: Condaghes, 2015. Usai, L. “La necropoli di Sa Pala Larga”. In La Preistoria in Sardegna. Il tempo delle comunità umane dal X al II millennio a. C., edited by T. Cossu, C. Lugliè (a cura di), 317-319. Nuoro: Ilisso Edizioni, 2020. Usai, L., Sartor, F., Costanzi Cobau, A. “Una nuova tomba dipinta della necropoli di Sa Pala Larga (Bonorva)”. ERENTZIAS. Rivista della Soprintendenza per i Beni Archeologici per le Province di Sassari e Nuoro 1 (2011): 13-38. Zedda, M. “I bovini nella Sardegna prenuragica”. In Nuove tecniche di documentazione e di analisi per una ricostruzione delle società dalla fine del V al III millennio a. C., Volume II, edited by G. Tanda (a cura di), 103-114. Cagliari: Condaghes, 2015. 105

9 More than meets the eye. Structured light and 3D enhancing strategies: the case of the Assa Valley rock art (Vicenza, Italy) Cinzia Bettineschi, Luigi Magnini, Emanuela Faresin, Laura Burigana, Armando De Guio, Giuseppe Salemi Abstract This chapter presents a pilot study aimed at investigating the morphological and morphometric characteristics of a selection of engravings located on the vertical walls of the Assa Valley (Asiago Plateau, Vicenza, Italy). 3D data acquired via Structured-Light Scanner was used to create textured 3D models with micrometric resolution. Morphometric data were converted and processed with LiDAR-derived enhancing techniques including multiple Hillshading, Openness, Sky-View Factor, and slope gradient. These visualisations improved the identification of the iconographic motifs, but also helped in reconstructing the tools and the techniques used for engraving. Finally, we compared and discussed a set of (semi) automated classification procedures in order to distinguish the different representations on the rock surfaces. Keywords Assa Valley (Vicenza, Italy) – Structured Light Scanning – production technology – DEM processing – (semi)automatic rock art classification 9.1 Introduction

represent the physical object “as-is”. Therefore, they can greatly increase the comprehension and the fruition of archaeological contexts and materials.

Archaeology represents an aspect of our historical memory that in the last decades has suffered transformations, violations or destructions for different human or natural factors. In this situation, the introduction of 3D technologies and virtual methods has been perceived as mandatory as it permits to preserve and explain the information embedded in cultural heritage through the application of different representation instruments. 3D acquisition and modelling technologies offer an important aid, as they allow us to

Manual tracing, frottages and photographs have represented an essential instrument of knowledge for the pioneering rock art studies, which allowed massive campaigns of recording and subsequent study of the engravings. These traditional methods could freeze the actual condition of a panel, becoming an essential document for its interpretation and preservation. The use of portable digital microscopes brought a first important innovation in recording and interpreting rock art panels (Marretta et al. 2011). However, with the introduction of digital survey systems and 3D models, the means of comprehension and communication of rock art sites have radically changed with 3D models representing a repository of information from which different kinds of representations can be extracted. The evolution of 3D modelling techniques and the development of more efficient systems for the visualisation of digital data highlight the added value given by the use of these methods in the archaeological field. The virtual model is a valid cognitive tool and is a fundamental medium through which the user can virtually interact with the object of interest. This technology can be applied to the world of cultural heritage for preservation, reconstruction, virtual restoration, research and promotion. Specifically, for this research, we employed structured-light acquisitions that have been only marginally explored in the study of archaeological rock engravings (Ruiz et al. 2022). This project focused on the documentation and study of the Assa Valley rock art, which is located in the municipality 107

Cinzia Bettineschi, Luigi Magnini, Emanuela Faresin, Laura Burigana, Armando De Guio, Giuseppe Salemi of Roana - Asiago Plateau (Vicenza), northern Italy. The local rock art is characterised by incised engravings, executed on vertical surfaces using both the filiform and the polissoir techniques. However, the visibility of the figures is very low. This is mainly due to the rough surfaces of the rocks, that are patinated with secondary minerals and rich in mosses and lichens. Another issue is related to the superimpositions of the figures that can alter the readability of some panels. The result is that the general public can recognize just a very small quantity of the effective representations. Moreover, most of the panels are located at a significant height with respect to the eyesight of the visitors, again preventing a complete realisation of the images.

in the areas of Tunkelbald and Sant’Antönle, which are characterised by the highest number and variety of engravings. Other significant concentrations can be found in the areas known as Romita, “Testa di Cavallo’’, ‘’Diga ``,’’Cava `` or’’Ponte di Roana” (Rigoni 2001). The first note on this rock art complex was published in 1982 (Leonardi et al. 1982), but it was only in 1983 that a complete catalogue of the representations was released (Priuli 1983). Further reflections on the area were also collected in the proceedings of the 1996 conference “Le incisioni rupestri della Val d’Assa: ipotesi a confronto”, published in 2001 (Arcà 2001; De Guio 2001; Leonardi 2001; Priuli 2001; Rigoni 2001, and others). The overall chronology is still very debated. While some authors suggest a pre-protohistoric date for some – or even the majority – of the images (Priuli 1983; Priuli 2001), others tend to attribute most part of the representations to the Middle Ages and the Modern period, with a dubious early beginning during the Second Iron Age for hut-barns and a few geometric representations (Arcà 2001). Considering the whole corpus of the engravings, most of the representations seem to be connected to the Christian worship or the civil sphere. Troletti (2015) is right in suggesting that images that used to be associated with solar fertility idols dating to the Bronze Age – such as in Romita, sector 3 or in Gelpach Valley – (Priuli 1983), should be better interpreted as monstrances, as unquestionably demonstrated for some Valcamonica occurrences (Troletti 2013). Possibly, the same can be said for the so-called vulvar signs that may represent the holy host itself (e.g., Tunkelbald, sector 12) and for some “complex signs’’ of dubious interpretation in the Sant’Antönle area (Rigoni 2001), that can perhaps be associated with goblets for the celebration of the Eucharist. On the contrary, some engravings were unanimously recognised as modern: there are for example various dates (the earliest being made in 1506), names, words and sentences, crosses, churches, and devotional offerings.

These are the main reasons that lead us to consider 3D acquisitions and data processing as a means for the objective documentation and subsequent virtual restitution of the engraved representations for preservation, virtual restoration, research and dissemination purposes. Currently, the acquisition of 3D point clouds can be very cheap and also very easy: structure from motion, laser scanning, stereoscopy, confocal laser scanning microscopes or even structured light acquisition are becoming more and more common for the documentation of archaeological sites and single materials (Lerma et al. 2010; Papageorgopoulou et al. 2010; Avanzini et al. 2015; Jalandoni et al. 2018; Magnini et al. 2019, and others). However, it is now time to think about a way to treat the 3D data in order to really enhance the microtopography of the surface and obtain an improved picture of the objects and contexts investigated. In this chapter, we propose a preliminary discussion on how landscape-level visualisation techniques coupled with structured-light acquisitions can really help in offering a novel perspective for the interpretation of the engraved representations. 9.2 The archaeological context The earliest known human presence in the Asiago Plateau can be traced back to the Palaeolithic and Mesolithic age, when nomadic groups of hunter-gatherers frequented the area on a seasonal basis (Broglio 1994; Broglio et al. 2006). A few sites were also occupied during the Neolithic, the Copper Age, and up to the Early Bronze Age. The best-known settlements within this time span are Covolo, Coldinechele di Velo, and Monte Corgnon, all in Lusiana (Vicenza) municipality, together with Erta and Piazzette sites, both in Marostica (Bianchin Citton 2001; De Guio 2019). The sites of Longalaita (Rotzo municipality) and Monte Corgnon yielded a huge quantity of materials related to the Middle and Recent Bronze Age. The Longalita hillfort was soon abandoned, probably in favour of the nearby Bostel promontory, whose earliest materials date back to the Recent Bronze Age. On the contrary, Monte Corgnon and Bostel show multiple frequentation cycles up to the Romanization of the area (De Guio 2001; Leonardi 2001; Magnini et al. 2020).

Suspending the judgement on the Remedello-like knives (Priuli 1983), which are too schematic for an explicit identification, a pre-protohistoric chronology seems very doubtful or eventually limited to geometric signs that are essentially timeless and can only be attributed to a preroman dating on the basis of other well-dated contextual elements, which, are currently lacking in this area. The Tunkelbald rock was chosen as the first focus of this project because it is one of the few sites in the Valley that was subject to a restoration campaign and an openair musealization. During the previous works of manual tracing, frottage and photographic acquisitions, the surface was divided in thirteen sectors for ease of referencing (Priuli 1983), that we will be also using throughout this chapter. The typology of the engravings comprises numerous anthropomorphic and anthropo-zoomorphic figures, but also weapons, crosses of various shapes and sizes, inscriptions, buildings, cup marks, a few animals, different kinds of geometric representations, from circles to asterisks, lines and polygons often of ambiguous attribution.

The Assa Valley rock art is generally concentrated on the vertical walls on the left side of the Valley and especially 108

More than meets the eye. Structured light and 3D enhancing strategies 9.3 Materials and Methods

The process of range map alignment consists of two steps: the first one is the manual choice of couples of homologous points on two contiguous sets of scans; the second one, is the automatic alignment aimed to minimise the mean distance and perfectly align the two acquisitions. • Range map merger (or fusion), to build a single triangulated mesh. This is a completely automatic operation and it is necessary to verify that the resulting model maintains the morphological and morphometric characteristics of the original: holes and anomalous connections between polygons may be present, easily recognizable as topological inaccuracies. • Mesh editing, to improve the quality of the reconstructed mesh. The acquisition process may have incomplete or uncorrected areas. This step requires the use of holes filling algorithms and the editing of the topological mistakes (for example cross section triangles or anomalous vertices). The aim of this step is to obtain a final 3D model topologically correct without unsampled or uncorrected areas (Faresin and Salemi in press).

9.3.1 Structured-light scanning A 3D model is a faithful and measurable digital representation of the object through the representation of its morphological and morphometric characteristics. We used a structured light system with a resolution of ± 0.1 – 0.4 mm (Figure 9.1). This method is based on triangulation and works by projecting a specific predefined light pattern that covers the whole (or part of the) surface. This scene is then captured by a typical digital image detector and processed in order to deduce the geometry from the deformations of the pattern in the digital image. This method is accompanied by texture acquisition (Zhang 2018). The data collected by the scans are X, Y, Z coordinate triplets of each single point analysed. Data acquisition and data processing with Optical RevEng software followed the standard steps of the 3D scanning pipeline (Laga et al. 2018).

9.3.2 From structured light to GIS

The post processing phases are:

To enhance the visibility of the engravings, the 3D point cloud was transformed into a grid Digital Elevation Model (DEM). In this way, we were able to use a series of classic topographic image-enhancing techniques developed for landscape-level LiDAR data (as already proposed for the “coinscapes” in De Guio and Magnini 2019). The effectiveness and consistency of this protocol is granted by the analogy between the data acquired by the two sensors: both, in fact, produce a point cloud as

• Range map alignment, in order to put all the single range maps into a common coordinate system where all the scans lie aligned on their mutual overlapping region. The pairwise ICP (Interactive Closest Point) alignment algorithm, followed by a global registration, was used. An automatic pre-alignment technique was used during the acquisition phase to improve this task and to verify in real time the quality of the acquisition.

Figure 9.1: Left: 3D acquisition with Cronos Dual (Open Technologies), a structured light system. Right: Preview of the range map acquired.

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Cinzia Bettineschi, Luigi Magnini, Emanuela Faresin, Laura Burigana, Armando De Guio, Giuseppe Salemi output of the acquisition from which information about the morphology/ topography of the object/ landscape can be derived (Opitz 2012).

sometimes V-shaped. Considering the dimension of the grooves and their section, the instruments used must have possessed tiny, hard and regular edges, most probably metallic. The profiles suggest a discreet (U-shaped) or high (V-shaped) sharpness, and either a conical shape (perhaps connected to the use of awls or burins) or a flat and small surface (possibly knives). The regularity of the engravings implies that the original tracing was performed with speed, spontaneity and confidence, even if there are examples of errors or afterthoughts. Cup marks are generally characterised by a conic section, produced by pointing a blade and drilling with rotary movements; due to the softness of the rock, this method could sometimes cause flaking and detachments, which explain the irregular contour of many occurrences.

The first step of the protocol is to export the point cloud in easily manageable formats for the widest range of software (including GIS software). In our experience, text files that report the coordinates of points in three dimensions (for example .asc or. xyz) offer excellent versatility of use, if compared to complete 3D models both TIN and raster. The second step is to convert the point cloud to a Digital Elevation Model. This procedure can be implemented, for example, by converting ASCII files to 3D raster surfaces and finally processing them as a Digital Elevation Model. The conversion and enhancing procedure can be summarised in the following steps:

This type of analysis is particularly valuable as it can assist in understanding if more tools were used for a single representation or if there is a technical trend in the figures of a scene that may suggest the presence of one or more authors for the composition.

1. Exporting the point cloud in easily readable format (.xyz or .asc files). 2. Importing the model of the study area into a GIS environment. 3. Creating a raster DEM from the point cloud. 4. Applying the selected DEM enhancing procedures on the raster file.

9.4.2 3D enhancing strategies The image data achieved with the described procedure were then treated with some of the best known and most frequently used (in the archaeological field) visualisation algorithms, in order to take advantage as much as possible of the acquired images and their information potential1. Hillshade, positive and negative Openness, slope gradient and Sky-View Factor algorithm were implemented on our 3D data. The most basic of the image treatments presented here, Slope gradient computation (or more simply Slope), conveys the slope distribution of an observed area by converting a map of elevation values in a gradient map. It calculates the maximum rate of elevation change (expressed in degrees or in percentile) between each image cell and its neighbours (Challis et al. 2011). Hillshade (Marsik 1971; Horn 1982) (also called shaded relief) is, on the other hand, probably the best known of the mentioned algorithms: it operates in a very intuitive way, as it replicates the natural effect of the illumination on a surface. The analysed map is illuminated by an artificial source of light, of which the user can set two basic parameters: the altitude (vertical angle) and the azimuth (horizontal angle). This is a common, but very effective technique that can highlight efficiently even small details by casting their shadow thanks to the lateral illumination. The downside is that some surface discontinuities parallel to the light orientation may this way not be visible, hence the light source position must be chosen attentively and, in some cases, it is advisable to illuminate the studied surface from different angles. This is not much different to what is commonly done on 3D models, for example using Meshlab or other dedicated software, by manually moving the light source to better visualise the details of

9.4 Results and Discussion 9.4.1 Notes on the engraving technology The incised rock art of the Assa Valley is characterised by a combination of thin lines (called filiform or graffiti) and thick lines (known as polissoir), that constitute the most common occurrences. Simple, thick polissoir lines are usually associated in the literature to sharpeners: i.e., rocks which were traditionally used for sharpening stone axes, metal blades or working tools. Both these techniques, graffito and polissoir, are common in the Alpine region, and have been in use from prehistory to modern and even contemporary times (Bianchi 2016; Sansoni et al. 2016 and cited bibliography). Incisions were obtained by scratching multiple times the rock surface with different kinds of tools (lithic or metallic), and producing grooves ranging from approximately 500 µm to a few mm. Given the low hardness of the Assa Valley rock outcrops, sometimes the walls could even be prepared beforehand by flattening or carving the surface in order to limit its irregularities (Arcà 2001). 3D models can also help in the technological investigation of the tools and the engraving practices, potentially helping to identify figures produced using the same tool and/ or similar technical solutions. Moreover, they offer an unparalleled help for recognizing and studying the superimpositions among the figures, which is fundamental for an Harrisian seriation of the signs and, ultimately, for proposing a relative chronology of the representations.

 Slope gradient, hillshade, and Principal Component Analysis of 16 hillshades were computed using ArcGIS, while Positive/ Negative Openness and Sky-View Factor were calculated with SagaGIS. 1

Figure 9.2 shows that the engravings could be made of a single or from multiple lines, sometimes rounded, 110

More than meets the eye. Structured light and 3D enhancing strategies

Figure 9.2: DEM-derived engraving sections visualized with the software Global Mapper 15.0 exemplifying the technologies identified in the Assa Valley rock art.

111

Cinzia Bettineschi, Luigi Magnini, Emanuela Faresin, Laura Burigana, Armando De Guio, Giuseppe Salemi the morphology. The use of hillshade helped to improve the graffiti visibility, as in the case of the Diavoletto (“little devil”) in sector 12 (see figure 9.3), this is especially noticeable observing the tiny lines of the objects the demonic figure is holding in hands, the shape of his right arm or the cup marks in proximity. Many more small cup marks were also detected with the aid of the Sky-View Factor algorithm (Kokalj et al. 2011). In many cases, in our image processing experience, Sky-View Factor proved to be one of the most informative visualisation techniques, being especially useful in exposing narrow depressions. The method consists in quantifying the visible portion of the sky sphere cap from each data spatial unit (corresponding to a pixel in the digital image). The SkyView Factor is calculated according to three set values: a vertical angle with which the user determines the horizon line, a given number (from 8 to 32) of search directions according to which the artificial “illumination” is oriented, and a maximum search radius directly proportional to the size of the investigated features (in other words, a large radius exposes better larger relief features whereas a small radius exposes tiniest and more complex features).

the squared frame (see figure 9.4, right). We also attained some significant results on sector 12 where, thanks to the digital acquisition, some differences and additional details were spotted in the comparison with the previous interpretation of the inscription (see figure 9.4, left). 9.4.3 Classification and (semi)automatic recognition 9.4.3.1 A semi-supervised classification analysis for 3D data processing Both supervised and unsupervised classification were adopted to attempt a quantitative evaluation of the mentioned visualisation techniques on three test subjects: the Diavoletto, a representation of a hut (Capanna) and a palimpsest in the area called P10. The images processed through hillshade (Marsik 1971; Horn 1982), positive and negative Openness (Yokoyama et al. 2002), slope gradient and Sky-View Factor (Kokalj et al 2011) algorithm were projected on a GIS platform2 and analysed in order to assess their efficiency on Val d’Assa rock art visualisation. The analysis process (see figure 9.5) was programmed taking into account four evaluation criteria:

Another visualisation technique that is rapidly gaining popularity in the archaeological field is Openness (Yokoyama et al. 2002), that can delineate successfully both concave and convex features in a raised-relief digital map. Openness value is computed using the mean zenith angle (positive Openness) or nadir angle (negative Openness) in at least eight directions from each image spatial unit. Positive and negative Openness algorithms worked successfully in combination to differentiate the bottom of the engraving (hence the lowest, thin line reached by the knife-edge), the inflection points and the whole trace caused by the repeated scratching on the rock.

• size of the area related to the incision (an auto-optically determined feature here simplified as trace feature), in other words, the pixels useful for identification; • consistency of spectral values within the trace feature, assessed by measuring the extent of its internal spectral range; • prominence of the trace feature tone, measured by comparing its mean spectral values to the values of the whole sample area; • the trace features texture prominence, meaning the distinctiveness of its texture compared to the whole sample area.

One of the most enigmatic panels we examined is located in sector 10, part of which at some point likely served as a sharpening surface for the knife blades. Given its complexity, we choose in this case to further aid our investigation by means of Principal Component Analysis or PCA, which also allowed us to overcome the static light source issue related to the hillshade algorithm. PCA is one of the most common and widespread procedures in remote sensing studies of landscapes. It is a method of multivariate statistics that merges the information of a given group of images in a new set of data, the so-called principal components (Lillesand et al. 2011, 536). The first elements of the generated series, which can be combined as RGB bands for a more complete visualisation, contain the features more frequently present in the original set and therefore are the most useful for the investigation; the result of their combination is in fact a false colour composite image of the first three components. Although the thus processed data may be less easy to interpret, the simultaneous visualisation of features in the entire scene, emphasised by multi-directional illumination, grants a sensible increment of information compared to the traditional mono-directional hillshade. In the case of sector 10, the PCA helped to better define the tiny lines in

As a first step, the visible parts of the inscriptions were drawn as polyline vectors on a new GIS layer; a first set of samples (Sample 1) was cut out from each image with a mask obtained from a 2 inches buffer from the polyline. The new images histograms were then manually manipulated to determine the visibility threshold of the incision in each observed treatment. Both the quantity of pixels (useful pixels, UP) and the spectral range (inner coherence, IC) in the resulting trace features were then measured. A second set of larger samples (Sample 2) was then extracted after adding to each trace feature area an arbitrary buffer of 5 inches. Within each new sample, the first information came from the comparison of the trace feature mean spectral value with its surroundings. A quantity of the trace feature spectral prominence (SP) was thus calculated: |trace feature mean spectral value – sample 2 mean spectral value|

  All classification operations were performed using Esri ArcGIS 10.2 (ArcMap Classification toolbox). 2

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More than meets the eye. Structured light and 3D enhancing strategies

Figure 9.3: Image processing of Diavoletto (detail of sector 12): hillshade (a); Sky-View Factor (b); slope gradient (c); positive Openness (d); negative Openness (e); graphic rendering of the visible trace (modified from Priuli 1983) (f).

Figure 9.4: Principal Component Analysis applied on an inscription in sector 12 (left) and on a portion of sector 10 (right).

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Cinzia Bettineschi, Luigi Magnini, Emanuela Faresin, Laura Burigana, Armando De Guio, Giuseppe Salemi

Figure 9.5: Sector 10: Hillshade visualization analysis (a), tresholding of Sample 1 area (b), trace feature extraction (c), Sample 2 (d), ISODATA clustering (e) and trace cluster/ trace feature intersection (f).

For the last evaluation (pattern prominence, PP) we took once more into account the second set of samples, on which we run the ISODATA clustering algorithm (Ball and Hall 1975) that reiteratively assigns each raster cell to a given cluster by computing the minimum Euclidean distance. We carried on the classification dictating a number of only 2 clusters, since we aimed at a pattern macro-differentiation between the trace and its close surroundings. The cluster compatible with the incision area (trace cluster) was then superimposed to the trace feature; the intersection areas in all samples were subsequently compared to the respective trace clusters, with the goal of finding the one with a better correspondence:

In all three objects of study the slope gradient had the worst results and the Openness algorithm got the highest score, the latter therefore proving itself as the most effective 3D visualisation processing among those examined. This looks particularly evident in the case of P10 test area, where the incision is deeper, whereas in the Capanna case, where the rock is scratched less profoundly, the treatments scores are more closely matched (Figure 9.6). The trace features (to which had been assigned a unique value of 1) extracted from all processed images were also combined through an overlay operation of map algebra (sum), in order to produce overall visibility maps (Figure 9.7). This simple procedure helped us to get an idea of which parts of the inspected subjects are less evident and therefore whose legibility may be put more at risk by natural or anthropic agents.

intersection pixels * 100 / trace cluster pixels The results (UPs, inner coherence, spectral prominence and pattern prominence) were finally all converted in percentage values and put together as means:

9.4.3.2 Object-based image analysis

(UP% + IC% + SP% + PP%) / n of treatments

Object-based image analysis is a classification process based on image-objects instead of pixels. Image-objects are homogeneous portions of an image derived from a segmentation process that divide the scene according to

thus, obtaining comparable overall ratings for each tested area. 114

More than meets the eye. Structured light and 3D enhancing strategies

Figure 9.6: Graphic display of results through Kivat diagrams: Diavoletto/ little devil (a), Capanna/ hut (b), P10 (c) test areas; overall comparison histogram.

different, user-selected algorithms (Baatz and Schäpe 2004).

to the real archaeological objects. The scale parameters were determined through a trial-and-error approach. We tested two different methods of classification: a Nearest Neighbour (NN) classification and a rule-based classification (Figure 9.8). Although both techniques automatically differentiate between intact and fractured rock, the classification between anthropic and natural engravings required more attention.

According to the types of engraving technology recognized in the rock art of the Assa Valley (see section 4.1), it is possible to distinguish the traces into two main classes: the graffiti (thin lines) and the polissoir (thick lines). Both of them are characterised by specific technological features that allow a general distinction and classification. As noted above, a third class of signs is represented by cup marks. In addition to the engravings, the rocks are also subject to detachments of natural or undetermined origin that can be sometimes hardly distinguishable from intentional representations, both by the software performing a (semi) automatic recognition and by the expert human operator.

Four classes have been implemented in the nearest neighbour classification of sector 11: Natural Rock, Rock Detachments, Graffiti and Polissoir. For each class, between 20 and 30 image-objects were carefully selected as samples. The result of the classification shows a high quality in the distinction between the class Natural Rock and the other three classes but a lower value in the discrimination between the anthropic (Graffiti and Polissoir classes) and natural (Rock Detachment class) traces. Thus, while the two crosses have been correctly ascribed in the class to which they belong, the same cannot be said for the squared frame and the hut. The numerous image-objects that constitute the square engraving have been classified equally among the classes Graffiti, Polissoir and Rock Detachment. The hut, instead, has mostly been classified correctly (Graffiti class), but some anthropic engravings have been recognized as natural rock detachments.

In order to evaluate the potential of object-based image analysis (OBIA or ArchaeOBIA) for the classification of rock art engravings, sector 11 has been selected as a testarea because it contains examples of all the three engraving technologies listed above. On this sector, one can easily identify: two polissoir (the cross at the right and a square), two graffiti (the hut in the centre and the cross in the right bottom) and a few cup-marks scattered around the panel. According to Monna et al. (2018) and to our own internal validation protocol (see section 4.3.1), positive Openness is the most suitable DEM enhancement to highlight engravings in a rather planar surface. So, we decided to test the OBIA approach on sector 11 using this specific visualisation technique. First of all, a multiresolution segmentation was applied to the positive Openness of the 3D model. This type of segmentation is the most common for the analysis of archaeological contexts (Magnini and Bettineschi 2019; 2021), because it allows the operator to create image-objects which are more similar

For the rule-based classification, we decided to implement one more class, the Cup-marks, in addition to the previous ones. The rule set was realized in subsequent steps according to the complexity of the archaeological objects to be classified. First of all, two classes of recognition have been applied (Natural Rock and Rock Detachments) based on the spectral value of the positive Openness. As for the Nearest Neighbour analysis, the classification was able to discriminate with a good level of precision 115

Cinzia Bettineschi, Luigi Magnini, Emanuela Faresin, Laura Burigana, Armando De Guio, Giuseppe Salemi

Figure 9.7: Capanna/ hut incision visibility in hillshade (a), slope (b), negative Openness (c), positive Openness (d), and SkyView Factor (e) processed images; synthesis overlay (f).

and accuracy between the two classes. After that, we isolated the thick Polissoir lines from the general class Rock Detachments using their textural homogeneity and their lowest spectral values in the positive Openness. These two features, however, do not define univocally the Polissoir class, because Cup-marks share similar values. In order to distinguish between Polissoir and Cup-marks, the roundness values were considered discriminatory; cup-marks, indeed, have a very rounded geometry. The most problematic part in the rule set creation was the recognition of the Graffiti class, because the characteristics of these incisions tend to overlap with

those of natural rock detachments. Spectral features alone do not provide an adequate number of variables to unequivocally discriminate between the two classes, so geometric/ dimensional features have also been used. In general, graffiti is composed of a thin and elongated engraving that is rather limited in space; so, it was decided to classify all image-objects that had these characteristics in addition to a concave profile. Another point to be considered in the classification of complex archaeological objects (as defined in Magnini and Bettineschi 2019), is the presence of interruptions that determine an absence of continuity in the representation. This, in the digital 116

More than meets the eye. Structured light and 3D enhancing strategies

Figure 9.8: Sector 11: final, segmented NN classification (above) and final, segmented rule-based classification (below). Blue: natural rock; green: rock detachments; yellow: polissoir; pink: cup-marks (only rule-based); red: graffiti.

domain, is concretized in the presence of several imageobjects that compose a single archaeological object. This issue can be partially overcome by considering relational features among the image-objects of the same class (or between different classes) in hierarchical perspective. In the specific case study, the segments representing the hut are generally very close to one another.

of the natural rock detachments. To overcome this issue, we applied a set of rules which are tailored for this specific case study, and should not be employed during an eventual automatic re-application of the same rule set in a new engraved panel. In general terms, using tailormade rules limits the re-applicability in other contexts, but significantly boosts the performance on the specific case study.

Despite classifying with a high degree of accuracy all of the anthropic engravings, the results of the image analysis still showed several commission errors in the recognition

For example, the graffiti of sector 11 have a well-defined orientation with respect to the random distribution of the 117

Cinzia Bettineschi, Luigi Magnini, Emanuela Faresin, Laura Burigana, Armando De Guio, Giuseppe Salemi natural cracks. This object-feature was thus used to refine the classification of the Graffiti class and delete some noise.

The application of remote sensing techniques and image enhancing algorithms proved further important to emphasise micro-morphology, increasing both qualitatively and quantitatively the information about the real objects. Moreover, the enhanced images show much more than what is visible today without the need of aggressive cleaning of the surfaces, which may put at risk the preservation of the engraving themselves. Coupling the various enhancing strategies, it is possible to obtain a clearer picture of the overall representations, adding a few more details to the manual tracing currently available (Priuli 1983). The potential of Object-Pattern-Scenery Recognition (OPSR), and in particular of object-based image analysis, opens further scenarios for the near future of rupestrian archaeology.

The comparison between the results obtained with the two classification techniques (NN and rule-based) highlights advantages and disadvantages of each methodology. Both methods offer an objective and quantitative approach to data analysis; however, while the nearest neighbour classification is considerably more inaccurate (especially in terms of commission errors), it has the advantage of being much less time-consuming with respect to the rule-based classification. On the other hand, the rulebased classification offers better accuracy, both in terms of omission errors (only some cup-marks were wrongly classified) and commission errors, but the rule-set creation is more time-consuming and requires a significant fine-tuning that may lead to problems during future reapplications. Then again, the two methods have proved to be particularly useful both in speeding up the analysis of data and in contributing to the interpretation phase.

Our hope is that manual tracings and 3D acquisitions will be more and more integrated into the operational routine of rock art studies according to the specific context, especially in the case of problematic superimpositions, or visibility issues, in order to combine the different types of information that can be derived from the two complementary approaches.

9.5 Conclusions and Perspectives In conclusion, it is important to underline that this contribution is not intended to say that digital acquisitions perform better than manual tracings. That would be very far from the truth. Manual tracing are interpretative studies in themselves, because the knowledge and the ability of the human operator offer a fundamental help for example in the differentiation between fractures and incised lines that can speed up the whole post-processing and classification procedure. Despite the differences between the tracing of the same panel made by different field operators3, the importance of manual recording goes beyond the issue of the precision and accuracy of the documentation per se: in fact, this method remains fundamental because it creates a connection between the operator and the contexts, offering a window on how the engravings were possibly made, by facing all the challenges of the strange positions that one needs to assume to be able to trace them, which are often similar to those that were used when first producing them.

Finally, the opportunities offered by 3D models transcend the idea of a passive preservation and foster innovative approaches for the dissemination of the results, for public involvement and eco-cultural resource management. In the case of the Assa Valley rock art, designing a dedicated app for tablets, smartphones or even smart glasses including GPS-guided tours and mixed / augmented reality experiences could truly boost the interactivity and immersivity of on-site visits, appealing to new audiences at local and national level. All engravings – even those which are too faint or corroded to be perceived with naked eyes – could be highlighted with different colours, magnified, manipulated and described with short notes and capitations, adding bonus features regarding connections to other rock art contexts and comparisons among specific panels. This would also imply lower maintenance costs, as there would be no need of a constant cleaning of the surfaces (except when required for preservation issues), and could also encompass the possibility to virtually restore images and signs that were previously damaged.

Digital acquisition, however, is a reproducible and objective method for recording and preserving the rock art panels and scenes. It offers a powerful tool to quantify the iconographic and morphometric characteristics of the engravings and produce a single, accurate and repeatable description. The very high-resolution models obtained form the basis for further specialised studies for example on the manufacturing techniques or on the iconographic characteristics of the artefacts, as it was presented throughout this chapter.

Digital acquisitions are also the founding core for creating virtual visits to the archaeological sites. In time of pandemic, the potential of this approach is apparent (Brogiolo and Chavarria 2020): experiencing digital tours or walkthroughs from the couch is not only a way to reach new audiences all around the globe, but may become the only possible solution for granting a continuity of the cultural offer in periods of crisis. Author contributions

  See for example the huge differences in the tracing of the “diavoletto” (little devil) in Tunkelbald, sector 12, published in Leonardi et al.1982 and in Priuli 1983: not only the facial expression is different, but various details (e.g., the elbows) and cup marks do not correspond between the two manual restitutions. In this sense, 3D models offer an unbiased representation of the actual engraving “as-is”. 3

The introduction is due to CB, EF, and GS; the archaeological context to CB and ADG; the section on structured-light to EF, and GS; section 3.2 from structured light to GIS was written by LM; CB wrote the notes on 118

More than meets the eye. Structured light and 3D enhancing strategies

Table 9.1: Synthesis of the processed image values collected during the visibility analysis. Pixels in Sample 1

Visibility treshold* (manual)

Inner coherence - IC (%)

UP (Useful Pixels)

% UP in Sample 1

Pixels in Sample 2

Mean value (Sample 2)

Mean value (trace feature)

MV (Sample 2) - MV (UP)

Spectral Promin­ ence - SP (%)

ISOcluster (TF pixels)

Intersection (pixels)

Pattern Promin­ ence PP (%)

OVER­ ALL

HILL

623356

106

41.73

251399

40.33

1935572

127.65

57.10

70.55

27.78

861989

251399

29.16

34.75

SVF

623356

100

39.37

203214

32.60

1836926

153.25

55.53

97.72

38.47

544126

203214

37.35

36.95

N OP

623356

92

36.22

188962

30.31

1793659

158.02

27.64

130.38

51.33

932146

188962

20.27

34.53

P OP

623356

101

39.76

296240

47.52

1904020

171.90

17.10

154.80

60.94

685905

296240

43.19

47.86

SLOPE

623356

48

18.90

125480

20.13

1710800

31.45

55.94

-24.49

9.64

769793

125480

16.30

16.24

HILL

970357

179

70.47

218781

22.55

2,142,852

205.67

119.21

86.46

34.04

539355

218781

40.56

41.91

SVF

970357

114

44.88

288322

29.71

2,161,855

158.40

63.16

95.24

37.50

588703

288322

48.98

40.27

N OP

970357

154

60.63

375033

38.65

2,255,500

156.10

71.06

85.04

33.48

1286539

348540

27.09

39.96

P OP

970357

103

40.55

276582

28.50

2,142,728

193.42

20.93

172.49

67.91

844539

276582

32.75

42.43

SLOPE

970357

42

49.41

330538

34.06

2,229,167

32.97

50.93

-17.95

7.07

1075951

330538

30.72

30.32

HILL

1952429

190

74.80

944846

48.39

4,020,211

181.38

106.37

75.01

58.76

1289177

746171

57.88

59.96

SVF

1952429

112

44.09

902599

46.23

3,904,469

138.09

47.43

90.66

71.03

1412006

902599

63.92

56.32

N OP

1952429

114

44.88

410340

21.02

3,707,236

179.65

36.90

142.75

111.84

2123132

410340

19.33

49.27

P OP

1952429

127

50.00

1082790

55.46

3,983,695

153.23

20.39

132.84

104.07

1600277

1082732

67.66

69.30

SLOPE

1952429

43

16.93

693018

35.50

3,990,343

35.48

54.62

-19.14

7.54

1907702

693018

36.33

24.07

Diavolo

Capanna

P10

*All values are expressed in a 0-255 value range, with the exception of slope gradient, with a range of 0-85

119

Cinzia Bettineschi, Luigi Magnini, Emanuela Faresin, Laura Burigana, Armando De Guio, Giuseppe Salemi the engraving technology; the section on 3D enhancing strategies is due to LM and LB; LB also wrote the section on semi-supervised classification, while LM the one related to object-based image analysis. The conclusions are by CB. All authors read and approved the final draft of this chapter.

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10 Rock art superimpositions in Cerro de los Indios 1 (Santa Cruz, Argentina): unravelling the sequence using digital technologies Agustina Papú Abstract This chapter aims to study rock art superimpositions in Cerro de los Indios 1, in order to evaluate changes in the way groups interacted with pre-existing representations. CI1 was recurrently occupied by hunter-gatherers during the last c. 4000 years BP, and has an important concentration of rock art involved in superimpositions. The application of digital technologies for processing photographs and tracing rock art, enabled the identification of a larger number and diversity of motifs as well as the sequencing of tonal series. The research also exposed a change around c. 2500 years BP in the interaction with pre-existing rock art. Keywords Relative chronology – hunter-gatherers – Patagonia – digital processing – image enhancement 10.1 Introduction

of the things that stands out about CI1’s art, is that most of its motifs are concentrated in a specific sector of the site and, within it, the majority of the representations are involved in sequences of superpositions (Aschero et al. 1999; Aschero and Guráieb 1995).

This chapter is focused on the study of rock art superimpositions in Cerro de los Indios 1 (CI1), an archaeological site located in the Province of Santa Cruz in the Argentinean Patagonia. During the past c.4000 years, CI1 was recurrently occupied by highly mobile hunter-gatherer groups, and throughout time these groups have imprinted their presence at the site with rock art. One

The study of rock art superimpositions can enable a better understanding of the decisions involved in pictorial practices. Aside from the fact that they allow the establishment of diachronic relationships between motifs, they also expose different attitudes taken towards the pre-existing rock art (Aschero 1988; Re 2016). Typically, panels with complex superpositions behave as cumulative palimpsests and the information available is hard to access (Carden and Miotti 2020; Keyser 2001). In cumulative palimpsests there is no actual loss of evidence, but the deposited elements are intermixed in such a way that discerning separate episodes becomes very difficult (Bailey 2007). This chapter will discuss the advantages in the application of certain digital tools in the process of unravelling a complex sequence of super­ positions at CI1. 10.2 Cerro de los Indios 1 CI1 is a rock shelter in the locality of Lago Posadas, in the northwestern area of the Santa Cruz Province (47° 35’ 43’’ S, 71° 43’ W). The site is located along the northern front of the hill known as Cerro del Indio or Cerro de los Indios, a dioritic-dacitic outcrop in the basin of the Posadas, Puerredón, and Salitroso lakes (see figure 10.1). Systematic research in the site began during the 1970s and since then a vast amount of archaeological remains have been recovered from excavations. Radiocarbon dating of these remains have suggested an occupation of the site in the course of two temporal segments: An Initial Block approximately dated to between 3900 and 3100 years BP and a Recent Block dated from around 1800 to 1000 years 123

Agustina Papú

Figure 10.1: (A) Location of the archaeological site CI1 within Patagonia (B) Outcrop known as Cerro de los Indios (C) Layout of Sector B in CI1, with location of the “main niche” and the excavated areas (based on the one presented in Guráieb 2012).

BP, with a chronological hiatus in between (De Nigris et al. 2004). It is important to note however that this hiatus does not correspond with a generalised abandonment of the region, it seems to be a particularity of the occupations in CI1, possibly related with changes in the role of the site in mobility dynamics within the basin (Aschero et al. 1999; De Nigris et al. 2004; Goñi and Barrientos 2004; Mengoni Goñalons and Yacobaccio 2000).

Studies suggest that CI1 held a prominent role in the mobility and settlement patterns of the hunter-gatherer groups that occupied the region. This site has been proposed as a convergence point recurrently visited by humans in the past since c. 3900 years BP. It would have been a part of the seasonal migration dynamics between the Andes Mountain range area, the Pinturas river basin and the western border of the Central High-Plateau (Altiplanicie Central) (Aschero et al. 1999; Figuerero Torres 2000; Mengoni Goñalons and Yacobaccio 2000; Aschero 2020).

CI1 has a large habitable surface area of about 240 m2, and is set in close proximity to permanent water supplies and diverse ecological environments, which made it a strategic location. The basin in which the site is located has a relatively low altitude that ranges between 100 and 300 m.a.s.l., providing more benign and protected conditions than neighbouring regions (Aschero et al. 1999; De Nigris et al. 2004; Mengoni Goñalons and Yacobaccio 2000; Guráieb 2012). These features made the basin even more appealing during the past c. 2500 years BP, when a series of climatic changes took place characterised by a decrease in the level of humidity in the area (Goñi and Barrientos 2004; Stine and Stine 1990). It has been proposed that these changes might have led to a reduction in the mobility of the groups that inhabited the region, and would have concentrated the population in areas where water was permanently available (Goñi et al. 2000).

The rock art present at the site has contributed to the notion of CI1 as a convergence or nodal point. This is mainly for three reasons: the first, CI1 has a significantly larger number of motifs in comparison to other contemporary sites in the vicinity; secondly, many of these motifs are involved in superimpositions; and thirdly, there are certain motifs present that share stylistic traits and hold strong similarities with rock art in neighbouring areas (Aschero et al. 1999; Gradin et al. 1979; Mengoni Goñalons and Yacobaccio 2000). The particularity of the site and its relevance was also suggested by the presence of a very unique motif that has no similar representations in the area (Aschero and Guráieb 1995; Guráieb 2012). This painting, often referred to as the “laberintiforme” (labyrinthshaped), is an umber spiral within two concentric circles with a total diameter of around 60 cm, located over 4 m above the ground.

This site is also characterised by a high visibility from a distance of over 25 km, reinforced by the weathered surface of the rock which reflects sunlight all throughout the day and makes the outcrop glimmer and stand out in the landscape (Mengoni Goñalons 1999). CI1 also works as a great vantage point, with a visibility of almost all the basin, reaching features 55 km away (Mengoni Goñalons and Yacobaccio 2000).

CI1’s art includes painted and engraved representations of both abstract and figurative motifs, in a diverse range of tonalities and techniques. The majority of the motifs are painted, and can be found in red, black, ochre, white, and umber hues. There is also a wide range of identifiable 124

Rock art superimpositions in Cerro de los Indios 1 techniques for the application of pigment preparations, including use of intermediaries, stencils, fingers, and the so called ‘impacts’. The latter is a term used to describe a specific kind of motif that appears as circular splotches located along the upper section of the available walls and under the ceiling of the rock shelters. It has been suggested that these representations were done using projectiles covered with leather or wool imbued with pigment (Aschero and Guráieb 1995).

rock art using various techniques, colours, and designs (Gradin et al. 1979; Aschero and Isasmendi 2018). 10.2.1 Chronological models for CI1 rock art The first systematic study of CI1’s art in articulation with the regional scenario enabled the delineation of a chronological model for the site’s rock art episodes. In the late 1990s C. Aschero proposed four phases of execution for the sites’ rock art history, and defined these phases as periods of time during which one or more tonal series could have been executed (Aschero et al. 1999). In order to estimate these chronological intervals, a series of factors were considered. These included the association between rockfall boulders (with and without paintings) and dated episodes of occupations within CI1, as well as information provided by other contemporary sites in the region with pigments in stratigraphy (Aschero et al. 1999; Aschero and Guráieb 1995).

Though there are motifs spread along the whole front of the site, these are unevenly distributed. When the first systematic recordings of the CI1’s rock art took place, the site was divided into two sectors separated by a concentration of boulders from past rockfall episodes: Sector A to the East, and Sector B to the West. The latter has a much more abundant assortment of rock art representations than sector A, as well as a larger concentration of other archaeological vestiges. Sector B also offers various sheltered areas along its 72 m front, and it is in this part of the site that the archaeological excavations have been focused on (Aschero et al. 1999).

The phases proposed are: An Initial phase (c. 3800 – 3200 years BP), an Early-Intermediate phase (c. 3200 – 3000 years BP), a Late-Intermediate phase (c. 3000 – 1400 years BP) and a Late phase (c.1400 – 900 years BP).

Around one third of CI1’s rock art representations are concentrated in a natural entrance in the rock referred to as the ‘main niche’, which is located in Sector B (see figure 10.1b). The base rock holds similar characteristics all throughout the site, yet there is a clear recurrent choice made by these groups regarding the placement of the representations. Within this niche over half of the motifs were identified in one single topographic unit (TU)1, most of them involved in a complex sequence of superimpositions, out of arm’s reach. It is in this TU that the aforementioned laberintiforme is found. Because there were no visible representations superimposed to it, previous studies have suggested that it had been intentionally maintained over time (Aschero and Guráieb 1995; Aschero et al. 1999).

According to this model, the Initial phase (c. 3800 – 3200 years BP) was composed of three tonal series: Red I, Black I and Umber I. These three series present strong relationships between each other, as well as certain similarities in the depiction of guanacos. This phase is also associated with the presence of labyrinth-type motifs, and the aforementioned impacts. The second phase, the Early-Intermediate (c. 3200 – 3000 years BP), consists of a second black tonal series. It is characterised by the presence of small headless guanacos (both isolated and in herds), schematic anthropomorphic figures, and painted animal tracks.

Up until recently, the main focus of rock art studies in CI1 has been centred around the identification of stylistic traits and the development of a regional chronological model for rock art representations in the area (Aschero and Guráieb 1995; Aschero and Isasmendi 2018; Aschero 2017). Paintings are earlier forms of representation in north-western Santa Cruz, while engravings appear as a regional phenomenon around 2500 years BP (Gradin et al. 1979; Gradin 1983); a moment that coincides with the aforementioned climatic and environmental changes. During the identification of regional rock art styles, an important focus was placed on the different ways in which guanacos were represented. The guanaco (Lama guanicoe) is an autochthonous camelid that has been identified as the main source of sustenance for the hunter-gatherer groups during the whole sequence of occupation in the area. And throughout the region this animal has been represented in

The Late-Intermediate phase (c. 3000 – 1400 years BP) encompasses five tonal series: Red II, Brown/Umber II, Green, White, Yellow-ochre. The red and brown series include abstract motifs such as lines, concentric circles, and assembled dots. Red II also has some representations of guanacos. The other tonal series in the phase consist exclusively of negative handprints (hand stencils). A significant portion of this time interval coincides with the identified chronological hiatus. However, considering that the hiatus does not coincide with a regional abandonment, it is possible to think that during this period CI1 could have been visited more sporadically or by a reduced number of individuals, which would have resulted in an inconspicuous datatable record in stratigraphy. The Late Phase (c.1400 – 900 years BP), consists in two engraved series and a third red painted episode. Engravings in both series are pecked, but the different degree of patina has helped discern between them. The so-called Engravings I includes curved geometric motifs, as well as human footprints and feline tracks. Engravings II on the

  Topographic unit is defined as a delimited area of the base rock upon which rock art representations have been executed. The limits of the unit are defined by features in the rock such as fractures or changes in its inclination/orientation (Re 2010). 1

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Agustina Papú other hand is mainly composed of bird tracks, very likely corresponding to choiques (Pterocnemia pennata), and guanacos. According to this model, this final red painted series consists mainly in the presence of simple geometric designs regionally associated with stylistic tendency known as ‘grecas’ (originally identified and proposed by Menghin in the 1950s).

analysis of the superimposition relationships within CI1 can contribute greatly to the process. 10.3 Methods and Techniques 10.3.1 Research potential of superimpositions The high concentration of superimposed rock art motifs in a site like CI1, holds an enormous information potential, waiting to be decoded. Studying superimpositions presents a series of opportunities. The first and most frequently used is its potential to identify diachronic episodes of rock art execution. They inherently imply that one motif was done prior to another and thereby serve as an indicator of relative chronologies (Breuil 1952; Chippindale et al. 2000; Keyser 2001; among others). In this regard, the study of the superimpositions in CI1 can provide more detailed information on the (relative) chronological relationship between certain types of motifs and tonal series. This in turn can contribute to the existing regional model of stylistic traits through time.

However later revisions on both the local and regional information, have started to provide a slightly different chronological scenario. The most recent developments in this line of investigation led by C. Aschero has proposed the identification of six Cerro de los Indios styles with associated chronologies: Cerro de los Indios A, B, C, D, E, and F (Aschero 2017; Aschero and Isasmendi 2018). Though this is still under revision and development, the information so far reads as follows: • Cerro de los Indios A (CIA) would have developed between c.5000 to 3800 years BP. Certain stylistic traits present in CI1 suggest an earlier occupation of the site than what the dated materials in stratigraphy have shown so far (Aschero and Isasmendi 2018). From around 5000 years ago the site would have been available for human occupation (Horta et al. 2015), and certain sectors in which this earlier rock art depictions are found have yet to be excavated. CIA includes a number of labyrinth-shaped motifs and guanacos corresponding to a design known as canon B. This particular representation, with a wide regional presence, is characterised by “amygdaloid-shaped” bodies, to which the hind and fore quarters have been added (Aschero and Isasmendi 2018). • Cerro de los Indios B (CIB) is dated to between c.3800 and 3500 years BP, and consists of the first black series. This style would correspond to the latest moments of the Initial Phase in the previous chronological model, and is characterised by oval-bodied representations of guanacos. • Cerro de los Indios C (CIC), dated to between c.3500 to 3000 years BP, corresponds to a second black series that is composed of small figures, and guanacos organised in herds. • Cerro de los Indios D (CID), dating from c.3000 to 2500 years BP, presents the first red tonal series consisting in small figurative representations. • Cerro de los Indios E (CIE), is dated to between c.2500 to 1000 years BP, and corresponds to the initial presence of engravings in the site, coinciding with the previously described Engravings I and II from the Late Phase of representations in CI1. There are different degrees of patina in the grooves suggesting at least two segregated episodes of engraving in time. • Cerro de los Indios F (CIF), dated to between c.1000 and 600 years BP, is based on another red series that is composed primarily of geometric designs, bird tracks and hand stencils.

Superimpositions also enable the possibility of identifying specific choices made in the past. Before the actual execution of rock art representations, a series of decisions took place, including the selection of the site and the desired placement of the motifs within it. These decisions would have been articulated with others regarding, for instance, the accessibility and visibility of each representation in the eyes of future observers. Features such as size, colour, and location, condition how someone else can or might interact with them later on in time. Superimpositions are one way in which these interactions are visibly manifested (Aschero 1988; Aschero 1997; Re 2016). The choice of painting or engraving a motif over another could be motivated by very different reasons, such as sacred locations, interactions between groups, or the recurrence of specific themes (Hernández Llosas 1985). In some cases, superimpositions can completely obliterate the underlying representations, while in other occasions the overlap of the new motif can be minimal, or might be recycling a pre-existing representation into a new design (Aschero 1988; Nash 2012; Re 2016). Each one of these decisions has its inherent implications, and though without ethnographic records, it’s not possible to truly identify set motivation, it is possible to observe different ways of interacting with the pre-existing rock art. The attitudes regarding previous pictorial representations can also be subjected to change throughout time. The study of ethnographic and historic records of South African hunter-gatherer groups, have suggested that by means of analysing rock art superimpositions, it is possible to discern changes throughout time in the way groups interact with pre-existing pictorial representations. The interaction between different rock art traditions can vary in accordance to changes in the relationship between groups, and / or between the groups and their environment (Louw 2016).

The development of this last chronological model is still being revised. The information provided by a detailed 126

Rock art superimpositions in Cerro de los Indios 1 The way people interacted with CI1 varied throughout time. Factors such as the intensity of occupation and the increasing levels of familiarity with local resources, suggest that the relationship with the site and its surrounding area developed and changed between chronological blocks. The so-called hiatus, that holds no correspondence with a regional abandonment, also presents a moment in time in which the role of the site within the groups’ mobility patterns differed (De Nigris et al. 2004; Guráieb 2012). This holds a particular importance because the chronological model based on the styles present, suggest that there are representations that would have been executed during the course of the hiatus (Aschero and Guráieb 1995; Aschero 2017).

photographs with Adobe Photoshop and DStretch. This helped identify motifs that were not visible in the field as well as resolve certain ambiguities. Adobe Photoshop was mainly used to alter lighting and contrast settings in the digital photographs. The modification of these values can later result in sharper and clearer distinctions when inputted into DStretch. This second software, designed by Dr Harman as a plugin of ImageJ, enables the application of predetermined filters which generate contrasts that can highlight the presence of pigments that are either too worn out or have been obliterated by another motif, and are unidentifiable with a naked eye in the field (Harman 2008). This newly processed information was then articulated with records from the field (particularly regarding tones and superimposition relationships), in order to create a digital trace of the rock art present. Tracing is a practice that predates the digital era, but informatic technology provides the opportunity of doing so without any risk of harming the rock art. For this part of the process, a vector graphics editing and design software was used. There are a few advantages of tracing with vector graphic software instead of a raster imaging-based one. Vector-based images are not subjected to distortion or loss of resolution when varying the scales, and the size of the final file is significantly smaller than raster-based tracings. For this particular investigation, Adobe Illustrator was used.

It is thereby possible to suggest as an initial hypothesis, that as the relationship between CI1 and its occupants varied, so would the way in which these groups interacted with the pre-existing rock art. In order to assess this proposal, a thorough analysis of the site’s superimpositions must be carried out. 10.3.2 Fieldwork Fieldwork was needed in order to carry out a systematic recording of the rock art motifs present in the site. The documented information included the type of motif, technique, colour, and – if present – details on evident superimpositions. This was accompanied with a thorough photographic record. Photography remains the most practical means for recording rock art, and has the advantage of exerting the least impact possible over the representations (McDonald 2006, 63).

This last software also has a feature that enables the construction of various digital layers in the tracing process. Each motif was therefore traced in a different layer which made the organisation of the sequence of superimpositions more versatile.

In this particular case, the detailed photographic record was also instrumental in the subsequent definition of tonal groups. Though this might sound controversial, and onsite recording with Munsell soil colour charts is a much more faithful tool, the configuration of CI1’s representations presented a dilemma. Like it has been previously stated, an important part of the site’s art is located out of arm’s reach. Consequently, this made it very hard to gain close access to certain painted sectors in order to define specific hues using the Munsell chart. In the cases in which it was not possible to use the Munsell chart, further detailed descriptions were noted down regarding observable similarities and contrasts in tonality between motifs.

Once the individual tracing of motifs was concluded the next stage consisted in the identification of tonal series. The information recorded on site was articulated with the one processed in the lab in order to identify groups of motifs that would correspond to a similar moment in time within the sequence of superimpositions. Tonal assemblages or tonal groups defined by similarities in hue, level of preservation, and technique were identified and organised in a sequence based on the order observed during the superimposition analysis. Motifs that shared these characteristics, even if they were not directly involved in superimpositions, were still considered part of the same series. 10.4 Results

Given the uneven distribution of motifs in CI1, the research focused on the main niche. The limits of this feature were delimited on the sides by changes in the direction of the rock. Because there were boulders with rock art within this area, the cavity’s drip line was used as an outer limit to determine which boulders were to be considered as part of the niche, and which were not.

Based on these new recordings, 539 motifs have so far been identified in CI1, 181 of them located within the delimited niche. Around 91% of the motifs present in the site are paintings (n=490), and 9% correspond to engravings (n=49). Over a thousand impacts were identified but an operational decision was made to consider groups of impacts within a same TU with similar hue, level of conservation and placing in the sequence of superimpositions, as a single complex motif with several constituting elements. The reason for this is that impacts are found in clusters, some made up of over fifty elements,

10.3.3. Application of digital tools The recorded information was later processed in the lab. The first step consisted in the optimization of the 127

Agustina Papú and it is not possible to discern whether each individual impact belonged to a unique episode, or if these were made in groups at a time. Though they are a very particular form of representation, the decision was made to apply the same criteria used throughout the investigation to classify abstract complex motifs: Groups of elements arranged together in a composition that portrays visual unity (Aschero 1988), generally based on shared morphology and hue, and taking into consideration similar degrees of deterioration as well as a shared location within the sequence of superimpositions.

tonal series such as the white and yellow ones from the Late-Intermediate Phase, were believed to be exclusively hand stencils. However, the image processing has helped identify a series of abstract motifs in both tonalities, such as concentric circles in yellow-ochre, an assemblage of white dots, and an articulation of white painted strokes. The digital alterations on the photographs also helped identify individual motifs that, because they had been painted in similar hues superimposed to each other, were originally classified as single undetermined ones. This particularly concerned representations in red and black hues.

The degree of conservation of the paintings in the site is very uneven. The areas outside the niche are more exposed to natural agents such as wind and sun, and thereby the paintings along these walls are more deteriorated than those sheltered in the niche. The level of exposure is also variable within this natural entrance in the rock. This had to be strongly considered at the time of organising in tonal series motifs of similar tonalities. Variances in hues in some occasions could be accounted as differential conservation problems.

Inside the niche, 24 topographic units were identified, yet of the 181 motifs within this sector, almost 60% are concentrated in a single one: TU 7, and within this TU, almost 75% of the motifs present are involved in sequences of superimposition. Because of this, the analysis began with the identification of tonal series within this TU. The process was done by articulating the information on superimpositions already identified in the digital tracings, with some stylistic traits of the existing chronological models.

Before processing the images one of the first things to stand out about the distribution of the motifs within the niche is that the representations along the walls of this cavity correspond almost exclusively to paintings (most of which are found outside the manual range of execution), while most of the representations on the boulders are engraved.

During the tracing process, each motif was drawn in a separate digital layer. In order to assemble individual motifs of a similar colour hue into a same tonal series the main requisite was that they shared the same relative chronological relationship with other tonalities in the sequence of superimpositions. For those motifs that were not involved in superimpositions, the incorporation into the sequence presented a problem. The only ones that were incorporated were those that fell upon the following stipulations: a) the outlying motif held a clear correspondence in hue with other motifs of a certain series, or b) a clear stylistic trait could associate it with others of an already identified series. If neither one of these requisites were covered, they were not included. This was particularly true for representations painted in black. The reasons for this are: a) there is a differential

The processing of images using the aforementioned digital tools enabled the identification of various new motifs that were not visible on site, and thereby had not yet been recorded. This was particularly significant in the processing of TU 7 (TU with the largest concentration of motifs), where the number nearly doubled after being digitally processed (59 new motifs were found) (see figure 10.2). Not only the quantity of motifs changed with the application of these techniques, but also the amplitude of the repertoire in terms of types of motifs. Prior to this analysis, certain

Figure 10.2: (A) TU 7- TU with the largest concentration of motifs in the site (B) Tracing of paintings in TU 7 done with vector graphics design software. There are some distortions in the tracing as a result of the transformation from 3D to 2D.

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Rock art superimpositions in Cerro de los Indios 1 degree of conservation throughout the panel, b) there are several identified episodes of black paintings, and c) dark brown and black pigments do not contrast as much with the DStretch filters, making ambiguities harder to resolve.

hues, but the digital processing placed this sequencing under discussion. In order to completely cover a dark representation with a lighter colour it is necessary to either add a very dense layer of the pigment preparation or significantly reduce the contrast of the darker figure and the background before painting over it. Either way, it is likely that if a motif in yellow, white, or a light red hue was painted over a black figure, the underlying representation would be identifiable for future observers. Specifically, if the density of the superimposed pigment preparation is more fluid, and / or if its rate of deterioration is faster than the underlying one. This has to be taken into account at the time of disentangling superimpositions. A dark tonality can be observable through the veil of a lighter hue, and give a strong impression of being above it. This, however, does not work the other way around; if a painting in a lighter tonality can be seen above the darker one, even if slightly so, that light motif would have more likely been painted on top. The problem is that without digitally processing the rock art record these subtleties are frequently lost. During this investigation, the contrasts generated with DStretch filters (particularly LDS, LAB, and LRE) enabled the observation of strokes of painting in lighter hues clearly overlapping the black motifs that had been originally described as being on top. This resulted in the re-evaluation of the order of several superimposition relationships throughout the panel. Some ambiguities however, were not as easy to solve, and remain under revision.

The greatest advantage that the configuration of motifs in TU 7 posed for this process was that in various parts of the panel, direct superimpositions linked together up to five different tonalities. This helped establish an initial diagram of the chronological sequence, to which the rest of the shorter overlapping episodes contributed. This first approach into the superimposition analysis enabled the identification of at least six tonal series. Series 1 corresponds to the earliest representations in the panel, the motifs-among which the laberintiforme is found. Series 2 is actually comprised by at least three episodes of black paintings (a, b, and c) but the variations in level of preservation along the TU and the fact that there are black motifs with very slight differences in hue superimposed to each other, makes it hard to discern which motifs correspond exactly with which one of these episodes. Series 3 consists of the representations painted in a dark red hue. Series 4 corresponds to the yellow-ochre motifs, Series 5 to those in bright red, and Series 6, the most recent in the sequence of motifs in TU 7, corresponds to an assemblage of paintings in white (see figure 10.3). One of the biggest challenges in this process was again associated with dark brown / black paintings. Field records and initial observations of TU 7, described certain black motifs as being painted above others in yellow and red

A particular aspect of the superimposition sequence that stood out throughout this process has to do with the

Figure 10.3: Sequence of tonal series traced and organized in separate layers.

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Agustina Papú labyrinth-shaped motif. Previous descriptions of this peculiar motif emphasised the idea that there had been an intention of not painting anything over it. Some white and ochre hues had been observed in between the lines, but nothing strictly overlapping it. However, the processing of the photographs with these digital tools exposed a very different scenario. Not only were superimpositions present, there were motifs of all the identified tonal series painted over it. Some of these superimposed motifs include an assemblage of black circles, a guanaco in dark red, a group of ochre concentric circles, an undetermined figure in bright red, and an assemblage of white dots. This motif was not maintained over time, but instead recycled and reappropriated (see figure 10.4).

presence of the aligned white dots that have been painted respecting the spacing in between the lines in the umber labyrinth. The observation of the proposed tonal series enabled the identification of a particularly strong relationship between Series 4 and 5 (yellow-ochre and bright red). Two yellowochre concentric circles are completely covered by motifs in red. The morphology of the overlapping motifs coincides almost exactly with the dimension of the underlying ochre representations. Another example of this interaction is the group of red lines painted surrounding a yellow-ochre circle. It is important to note that none of these motifs (the concentric circles with overlapping red figures, nor the ochre circle with surrounding red lines) were visible on site; they were only identified after processing the photographs with DStretch.

Generally, there seems to be a constant interaction between the series present in this TU. This is suggested by the mere presence of these “multiple” superimposition sequences directly joining various tonalities with each other. This interaction articulates the earliest umber depictions, through to the most recent white ones, as can be seen in the

The rock art representations along the other walls of the niche were painted in red and black tonalities. The fact that the relative timeline of tonal series proposed for

Figure 10.4: Sequence of execution of motifs in articulation with the laberintiforme. (A) Labyrinth-shaped motif, oldest representation in the niche corresponding to Series 1 (B) Series 2: comprised by several episodes of black paintings. (C) Series 3: Earliest red paintings (D) Series 4: yellow-ochre paintings (E) Series 5: bright red representations-in strong relationship with Series 4 (F) Series 6: white paintings.

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Rock art superimpositions in Cerro de los Indios 1 TU 7 identified two different hues of red and at several episodes of black paintings, makes it hard to integrate the representations in these other walls into the sequence. This is also made harder by the fact that paintings on the other walls in the niche show a poorer level of conservation than TU 7, which alters the observable tonalities.

This sharp change shows a clear break in the way the groups interacted with the pre-existing art. Up until this point, there had been a continuous articulation between the rock art representations, and a clear intention of overlapping new series of motifs over this already densely covered area of the site. But with this first engraved series comes a big change. These new representations broke away from an existing dynamic, stopped interacting directly with the pre-existing rock art and started using other available sectors. Once this change was made, the subsequent series remained in the more accessible areas.

The boulders within the niche have both painted and engraved representations. But it is important to note that the engravings are not superimposed over any previous painting. However, over some of these pecked motifs in TU 22, there is a later series of red paintings (a third red series, in a dark red hue) that is directly overlapping them. In some cases, the painting was added “filling” the grooves. These two series do not hold direct physical interaction with any of the ones painted along the walls of the niche.

It is interesting to note that this moment of change occurs during the time lapse identified as a chronological hiatus in CI1. During this period in which a certain distance was installed between these groups and the site, and in which climatic changes started restructuring the environment, there is an observable transformation in the attitude taken towards the pre-existing rock art.

10.5 Conclusion According to the existing regional chronological model based on stylistic traits, the motifs present in TU 7 were probably painted in the period between the initial occupations up until around 2500 years BP. This would also apply for most of the representation in the other walls of the niche. The majority of the motifs corresponding to this time frame were painted out of arm’s reach, which in itself poses a new set of questions regarding this activity.

During this investigation, the application of digital tools to process photography has increased significantly the number of motifs identified in the site (even doubled the field records in some cases). This level of image processing must therefore be applied for the rest of the site, which will very likely increase the total amount of motifs; particularly considering the aforementioned differential conservation. The next step in the analysis of superimpositions which is currently in place, is the use of a Harris Matrix to identify and structure the classification of the different types of superimpo­ sitions. This will enable a more detailed understanding of the interactions throughout time between overlapping motifs.

Around 2500 years ago a shift happened. Motifs that had been associated in the site with chronologies after 2500 BP, can be found in more accessible placings such as the boulders within the niche. Not only is there a significant change regarding the emplacement of motifs, but also in terms of techniques. It is around this time that the first engravings would have been done in the site (see figure 10.5).

As a final remark, in order to strengthen the chronological models, future investigations should contemplate the possibility of resuming excavations in the site.

Figure 10.5: Distribution of representation in the niche. (A) Overall view of the ‘main niche’ (B) Areas along the walls of the niche where representations were likely painted before c. 2500 years BP; location of TU 7 (C) location of representations after c. 2500 years BP; location of TU 22.

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Agustina Papú Acknowledgements

Bailey, J. “Time perspectives, palimpsests and the archaeology of the time”. Journal of Anthropological Archaeology. 26 (1) (2007): 198–223.

To Damián Bozzuto, Carlos Aschero, María Teresa Civalero, and the rest of our team. To María Pía Falchi, Anahí Re, Gabriela Guráieb and all the colleagues at the Instituto Nacional de Antropología y Pensamiento Latinoamericano. To the people in the communities of Perito Moreno and Lago Posadas. To the organizers of the IFRAO 2018 Congress: Centro Camuno di Studi Preistorici and the Cooperativa Archeologica “Le Orme dell’Uomo”. And finally, to the session coordinators at the IFRAO Congress where this work was originally presented: Julian Jansen van Rensburg, Bernadette Drabsch, and Rebecca Döhl, and all those who helped organise this publication.

Breuil, H. Quatre cents siècles d’art pariétal. Les cavernes ornées de l’age du renne. Montignac: Centre d’etudes de documentation préhistorique, 1952. Carden N. and Miotti, L. “Unravelling rock art palimpsests through superimpositions: The definition of painting episodes in Los Toldos (southern Patagonia) as a baseline for chronology.” Journal of Archaeological Science Reports 30 (2020): 1-16. Chippindale, C., de Jongh, J., Flood, J, and Rufolo, S. “Stratigraphy, Harris matrices and relative dating of Australian rock-art”. Antiquity 74 (2000): 285–286.

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De Nigris M. E., Figuerero Torres, M. J., Guráieb, A. G., and Mengoni Goñalons, G. L. “Nuevos fechados radiocarbónicos de la localidad de Cerro de los Indios 1 (Santa Cruz) y su proyección areal”. In Contra viento y marea. Arqueología de Patagonia, edited by T. Civalero, P. Fernández and A.G Guráieb, 537-544. Buenos Aires: Instituto Nacional de Antropología y Pensamiento Latinoamericano and Sociedad Argentina de Antropología, 2004.

Aschero, C.A. “Pinturas rupestres, actividades y recursos naturales: un encuadre arqueológico”. In Arqueología Contemporánea Argentina. Actualidad y Perspectivas, edited by H. Yacobaccio, 109-145. Buenos Aires: Ediciones Búsqueda, 1988. Aschero, C.A. “De cómo interactúan emplazamientos, conjuntos y temas”. Revista del Museo de Historia Natural de San Rafael. Actas y Memorias del XI Congreso Nacional de Arqueología Argentina (cuarta parte) (1997): 17-28.

Figuerero Torres, M.J. “Tendencias en el uso del espacio en Cerro de los Indios 1”. Arqueología 10 (2000): 203-239.

Aschero, C.A. “Cerro de los Indios 1 en la arqueología regional”. Presentation for the tourist guide training sessions at the locality of Perito Moreno. Unpublished report, 2017.

Goñi. R.A., Barrientos, G. and Cassiodoro, G. “Condiciones previas a la extinción de poblaciones humanas del sur de Patagonia: una discusión a partir del análisis del registro arqueológico de la cuenca del lago Salitroso”. Cuadernos del Instituto Nacional de Antropología y Pensamiento Latinoamericano 19 (2000): 249-266.

Aschero, C.A. “Cerro de los Indios 1: Importancia del sitio en el panorama regional”. Unpublished report presented to the Lago Posadas governing commission, 2020.

Goñi, R.A. and Barrientos, G. “Poblamiento tardío y movilidad en la cuenca del lago Salitroso”. In Contra viento y marea: arqueología de Patagonia, edited by M. T. Civalero, P. M. Fernández and A. G. Guráieb, 313324. Buenos Aires: Instituto Nacional de Antropología y Pensamiento Latinoamericano and Sociedad Argentina de Antropología, 2004.

Aschero, C.A., De Nigris, M., Figuerero Torres, M.J., Guráieb, G., Mengoni Goñalons, G., and Yacobaccio, H. ``Excavaciones recientes en Cerro de los Indios 1, Lago Posadas (Santa Cruz): nuevas perspectivas”. In Soplando en el viento. Actas de las III Jornadas de Arqueología de la Patagonia, 269-286. Buenos Aires: Presidencia de la Nación, Secretaría de Cultura, Instituto Nacional de Antropología y Pensamiento Latinoamericano, 1999.

Gradin, C. J. “El arte rupestre en la cuenca del Río Pinturas, provincia de Santa Cruz, Republica Argentina”. Ars Prehistórica II (1983): 87-149. Barcelona: Editorial AUSA.

Aschero, C.A. and Guráieb, A.G. “Informe al Instituto Nacional de Antropología y Pensamiento Latinoamericano sobre el sitio Cerro de los Indios 1 (Lago Posadas- Santa Cruz). Project: Documentación y Protección de Arte Rupestre Argentino”. Internal Report presented at the Instituto Nacional de Antropología y Pensamiento Latinoamericano. 1995.

Gradin, C.J., Aschero C.A., and Aguerre, A.M. “Arqueología del área río Pinturas (provincia de Santa Cruz)”. Relaciones de la sociedad argentina de antropología 13 (1979): 183-227. Guráieb, A.G. Tendencias tecnológicas, de selección de materias primas y diseño de artefactos líticos en la secuencia de ocupaciones del Holoceno Tardío de Cerro de los Indios 1 (CI1), lago Posadas, provincia de Santa Cruz. Universidad de Buenos Aires, 2012.

Aschero, A. and Isasmendi, M.V. “Arte rupestre y demarcación territorial: el caso del Grupo Estilístico B1 en el Área Río Pinturas (Santa Cruz, Argentina)”. Revista del Museo de la Plata “Dossier: Abordajes actuales para el estudio de los paisajes arqueológicos” 3 (1) (2018): 112-131.

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Rock art superimpositions in Cerro de los Indios 1 Hernández Llosas, M. I. “Diseño de investigación para representaciones rupestres”. In Estudios en Arte Rupestre, 25-36. Santiago de Chile: Museo Chileno de Arte Precolombino, 1985. Horta, L. R., Georgieff, S. M., and Aschero, C.A. “Chronology of bathymetric variations of the Pueyrredón-PosadasSalitroso lacustrine system during the Late Pleistocene to Early Holocene”. Quaternary International 337 (2015): 91-101. Keyser, J. D. “Relative dating methods”. In Handbook of Rock Art Research, edited by D. Whitley, 116-138. Walnut Creek: AltaMira Press, 2001. Louw, C. Interpreting superimposition in rock art of the Makgabeng of South Africa’s Limpopo Province. University of the Witwatersrand, 2016. McDonald, J. “Rock-art”. In Archaeology in practice. A student guide to archaeological analyses, edited by J. Balme and A. Paterson, 60-96. Malden: Blackwell Publishing Ltd, 2006. Mengoni Goñalons, G. Cazadores de guanacos de la estepa patagónica. Buenos Aires, Argentina: Sociedad Argentina de Antropología, 1999. Mengoni Goñalons, G. and Yacobaccio, H.D. “Arqueología de Cerro de los Indios y su entorno”. Arqueología 10 (2000): 193-201. Nash, G. “Temporal modes in rock art: how passive superimposition tamed the Iron Age warriors of the Valcamonica, Lombardy, northern Italy”. Arkeos 32 (2012): 91–102. Re, A. Representaciones rupestres en mesetas altas de la provincia de Santa Cruz. Circulación de información en espacios de uso estacional. Universidad de Buenos Aires, 2010. Re, A. “Superimpositions and Attitudes Towards Preexisting Rock Art: A Case Study in Southern Patagonia”. In Paleoart and Materiality: The Scientific Study of Rock Art, edited by R.G Bednarik, D. Fiore, M. Basile, G. Kumar and T. Huisheng, 15-29. Archaeopress Archaeology, 2016. Stine S. and Stine, M. “A record from Lake Cardiel of climate change in southern South America”. Nature 345 (1990): 705-708.

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11 The site of Nag el-Hamdulab in 360°: an alternative way to experience a story from the past Alberto Urcia, Alessia Brucato, Maria C. Gatto, Antonio Curci Abstract The digital era in the field of cultural heritage, including archaeology, has finally reached a mature stage, with better identified research questions, and the capacity to address and fulfil the needs and goals of the various sub-disciplines. Technological achievements, together with preservation issues and the need to disseminate results, have driven the development of exciting new systems for sharing knowledge with people all over the world. At the same time, this trend is producing an increasingly large amount of data that present ongoing challenges for effective management and storage, especially for the growing volume of 3D contents. Nowadays it is quite simple to produce graphically appealing layouts that are geometrically accurate and photorealistic, but remain difficult to keep them organised and graphically connected with all the related types of information. In this article we present our experience, with the Aswan – Kom Ombo Archaeological Project, in turning an important rock art site, Nag el-Hamdulab, into a complete and accessible interactive Virtual Reality Tour based on 360° photography (VRT360). This work mostly carried out using Virtual Tour Pro (VTP), a software by 3D Vista, provides an excellent case study in how to integrate 3D spatial data with a range of other types of site data, in a way that makes it easily and efficiently reachable to many stakeholders. Keywords Virtual Reality – Rock Art – Digital Archaeology – Egyptology – 360° Tours sites and disciplines, using appropriate study methods and the contribution of several specialists in archaeology but the introduction of digital technologies for the recording, documentation, analysis, and publication of most research results has featured prominently (Curci et al. 2012). Since 2009, the project has experimented with several tools and techniques to support fieldwork and data analysis. The large number of rock art sites required to potentiate the standard recording methods. The availability of increasingly powerful digital recording devices and software helped AKAP to move to a non-invasive and fully digital recording strategy aimed at increasing quality and efficiency (Urcia and Curci 2016; Urcia et al. 2018). Although the new technological approach is positively influencing the work of the entire project, this chapter will focus on the rock art that is a central feature within the AKAP areas archaeological records (Figure 11.1). For a long time, until the Ministry of Tourism and Antiquities in Cairo proclaimed a ban in 2011, the most common and well-known technique to document petroglyphs was ‘contact tracing’: using transparent plastic foils placed directly on the rock surface along with permanents markers (sharpies), carved figures or signs were recorded, mainly detecting outlines, infilled patterns, and damage (Anati 1976; Priuli 1984). After this ban, researchers in Egypt had to rapidly devise alternative ways to record rock art. Thanks to collaborations between several experts on our team, along with several interesting pilot projects, also AKAP had a chance to draft and test a new functional and rigorous recording methodology. Sharing experiences among colleagues and working simultaneously with specialists in epigraphy was important to improve and

11.1 Introduction The Aswan – Kom Ombo Archaeological Project (AKAP),1 has worked since 2005 to help preserve and enhance knowledge about the archaeological heritage of the area between the cities of Aswan and Kom Ombo in Upper Egypt. AKAP research includes a wide range of  The Aswan – Kom Ombo Archaeological Project, directed by M. C. Gatto and A. Curci, is now available to be visited online at www. akapegypt.org. 1

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Alberto Urcia, Alessia Brucato, Maria C. Gatto, Antonio Curci customise the workflow according to research needs and technical requirements (i.e., resolution, lighting, metrical accuracy etc.). One of the most challenging goals was to keep petroglyphs and landscapes graphically connected. The strict relationship between rock art and its environment must be preserved in the digital copy to preserve the original messages and meanings (Lippiello 2012). 3D imaging and 3D modelling offer interesting solutions to this problem, especially since Structure from Motion (SfM) has become so popular and accessible for archaeologists (Medici and Rossi 2015; Domingo et al. 2013; Domingo 2014; Urcia et al. 2018).

the physical taxation and incorporation of what at the time would have been a still somewhat loosely defined border area between pharaonic Egypt and A-Group Nubia. In the Nag el-Hamdulab cycle, the king appears prominently for the first time as both overseer and object of a celebration incorporating ritual, administrative, and fiscal elements. The entire assemblage forms the largest iconographic cycle surviving from the Protodynastic Period. Besides the Dynasty 0 / First Dynasty cycle, a few other rock art scenes have been found at Nag el-Hamdulab; some likely date to the Early Dynastic/Old Kingdom period, while others seem to be modern creations (the latter were found in a shelter labelled Locality 8, which for now is not included in the virtual tour). During the New Kingdom, an inscription was centrally positioned within the early drawings of Locality 7 – Panel B.

The ability to display and interact with an object in three-dimensional space significantly expands the possibilities for scientific enquiry, especially if the quality of reproduction is high enough to minimise the risks of misinterpretation due to subjectivity (Biagi 2018, 26-35).

From the tops of the inscribed hills, modern visitors, like the ancient participants in the activities depicted, have spectacular views of the Nile, the cultivated land, and the surrounding deserts. The first record of the Nag el-Hamdulab rock art site, pertaining only to its main tableau (current Location 7 – Panel A), dates already to the end of the nineteenth century (De Morgan et al. 1894, 203). The site was then visited again sometime between 1962 and 1969 by the Egyptologist Labib Habachi, who discovered the other clusters of the scenes, took a detailed photographic documentation (currently part of the Labib Habachi Archive preserved at Chicago House in Luxor), but never published the finding (Figure 11.2). About a decade ago, the late Nabil Swelim noticed a scene with a king wearing the White Crown (Location 7 – Panel A), in the Habachi’s photographs and inquired to colleagues for more information on the possible location of the unknown drawing. In the same year, the rock art locales within NH1 were relocated by two archaeological projects working in the area: the QuarryScapes Project and the Aswan – Kom Ombo Archaeological Project (Storemyr 2009; Hendrickx and Gatto 2009). It is only with this rediscovery that the full scope and significance of the Nag el-Hamdulab cycle became apparent. The AKAP has taken charge of the systematic investigation and final publication of the site, which are still ongoing. In 2019, a previously unknown large panel representing a unique hunting scene was discovered by looters and it is currently under study. Fieldwork is still ongoing at NH1 and more drawings could be found.

Despite the advantages of 3D modelling, there is an important aspect of rock art that cannot be reproduced without involving additional technologies: the visceral perception of distance and dimensions between depiction, landscape, and the observer. Petroglyphs are quite common in Egypt and can be found in many different contexts, ranging from ancient quarries or isolated boulders to entire khors and wadis. At a first glance, the relation between inscribed rock surfaces may appear random and inconsistent, but studies2 demonstrate that this is often not true and that subtle spatial relationships often underlie the selection and placement of individual petroglyphs. This is well illustrated by the site of Nag elHamdulab, the main subject of our Virtual Tour experience (Hendrickx et al. 2012). 11.2 The site of Nag-el Hamdulab Nag el-Hamdulab (NH1 in our records) is situated on the west bank of the Nile, about 6 km north of Aswan, in a sandy bay that opens to the Nile Valley west of the homonymous village (see figure 11.1). The bay is at all other sides surrounded by rocky cliffs. Two small saddles to the north and the west of the semi-closed basin give way to the large valley Wadi el-Faras, while a third small saddle connects the basin with the area to the south. A series of important rock art scenes, arranged in eight discrete groups of images and ranging in size from a few small figures to large and complex tableaux, represent an extended festival scene dating from the cusp of Dynasty 0 to the First Dynasty (c. 3100 BCE). An early hieroglyphic annotation accompanies the main panel (Location 7 – Panel A) of the ensemble, and supports, along with the iconography, a possible date during the reign of Narmer. The four signs making up the early text appear to describe a ritual, apparently the ‘Following of Horus’, which involved both the confirmation of royal ritual power and

Of course, having the opportunity to be in front of the original rock surface, immersed in stunning landscapes and connected to local cultures would be the best way to experience the site, its dimensions, the atmosphere and all the related sensations and emotions. As archaeologists, we feel privileged to have chances to physically access such wonders and this is also what motivates us to help preserve them and develop ideas to put them in touch with the rest of the world. Considering the technological advances that archaeology has made over the past 20 years and the importance of NH1, a series of questions arose: what are the best means to communicate our archaeological sites?

  See, for instance, our work in the Aswan region: Gatto et al. 2009; Lippiello and Gatto 2012; Gatto and Curci forthcoming. 2

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The site of Nag el-Hamdulab in 360°

Figure 11.1: Map displaying AKAP’s concession areas and Nag el-Hamdulab (NH1) location.

What are the available solutions to connect people to rock art sites if they cannot physically reach them? Is there a way to reproduce at least part of our on-site emotional/ sensorial experience in a digital copy?

(NH1 in this case) and its history. Panoramic, flat, bidimensional image files serve as backgrounds for the tour, on which additional data is linked using external contents and navigation/interaction commands. These backgrounds photographically reproduce the visible landscape that surrounded the camera and tripod during shooting (Figure 11.3). The images were recorded following a specific acquisition procedure and processed using software that stitched them into a single larger file (see chapter 5.2 – 5.3). Sometimes, it is enough to have a partial view-range of the surrounding space, if the focus goes, for example, on one or two vertical walls of a room or a rocky outcrop. However, in our case we wanted a full range of coverage, including the sky and the ground, reproducing the perspective of a real person standing where the tripod and camera are located. Virtual Tour Pro, the software that is described in this article (see chapter 7), wraps the panoramas around a virtual spherical shape, placing the user’s point of view therein. Whatever the eyes of the ‘invisible user’ are framing corresponds to what the real user sees in the computer browser or through his headset.4 But if all this must fit into a panoramic image, which is basically a rectangular bidimensional file, how can sky and ground be included? This is made possible

11.3 ‘Virtual’ what? Nowadays, terms like ‘virtual tour’, ‘virtual reality’, ‘story telling’ or ‘emotional engagement’ are certainly not unknown, especially in the field of Cultural Heritage. The literature is quite rich and in the last few years the use of virtual platforms had a sort of positive explosion due to the social and travel restrictions imposed by the COVID19 pandemic (El-Said and Aziz 2021). However, it is still easy to confuse or misuse terminology, so we will briefly describe the parameters of our VR project. First, our tour is a product of Computer Graphics, the discipline that digitally synthesises and manipulates visual contents (Hughes et al. 2013) and it is based on the interpolation between panoramic images that can be displayed in 360 degrees and navigated by users via computer browsers or headsets. The tour is intended to be an Interactive Digital Storytelling (IDS)3 tool, able to teach and spread information about the archaeological site   This term is borrowed by Škola et al. 2020, 3. For a specific meaning of these terms see also Bertrand et al. 2020.

  NH1 Virtual Tour is compatible to run with the most common headsets available on the marketplace, including the Oculus and HTC Vive.

3

4

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Alberto Urcia, Alessia Brucato, Maria C. Gatto, Antonio Curci

Figure 11.2: The most important scene of Location 7 before it got damaged (Photographed by Labib Habachi).

using applications commonly called ‘stitchers’ (in our case Stitcher V4) able to calculate the distortions, as when we unwrap the terrestrial globe onto a map and obtain a planisphere (Emery and Camps 2017).

angle’, ‘photo-mosaicking’ and so ‘panorama’, quickly grew into a new field which has continued developing to this day (Jacobs 2004, 1-2; Thompson 2015). Many methods of panorama have been invented so far: cylindrical, spherical, cubic, ‘reversed’, stereo, macro, video/sound, and finally ‘virtual’ (Jacobs 2004, 3-5). The term Virtual Reality (VR), although similar, should not be confused with Augmented Reality (AR), Mixed Reality (MxR), Augmented Virtuality (AV) or Simulated Reality (SR) that have substantial differences (Bekele and Champion 2019, 1-3). Using Tepe et al. 2018, 1 «Virtual Reality is a three-dimensional simulation environment where users can feel close to real life experiences in an artificial world developed with different devices and visualisation equipment, as well as interacting with other objects». After photography met the invention of computers, but especially from the 1970s onwards, the concept of ‘virtuality’ saw a fast growth, mainly to solve military and aerospace engineering problems (Mazuryk and Gervautz 1999; Cipresso et al. 2018). The significant developmental phase of VR happened during the 1980s and 1990s, when big companies began investing in affordable devices and software for recreational purposes, opening the era of video games. Gaming consoles became higher and higher performing overtime and the beginning of the twentyfirst century brought a substantial change in the market with the entry of the internet into daily life. The massive

If we open these panoramas as they are with a simple image viewer, we will notice that what we see makes no sense. In fact, it is necessary for a specific viewer to re-project what appears flattened back onto a spherical shape (this module is also included into VTP). These new re-shaped versions of the panoramas represent what we have called “viewpoints” in our tour. Each viewpoint is connected to a relational network of commands and information that guides the user to navigate the virtual site and interact (display, move, read, select) with the available contents. This short description and the following chapter should give a sense of how our tour works for those who are not familiar with this technique. 11.4 A brief background on VR (Photography) The attraction of having a wider view that can better present objects and the space in which they are represented, has its roots in the artistic panorama of the late 18th century. Once photography was invented in 1839, concepts such as ‘wide 138

The site of Nag el-Hamdulab in 360°

Figure 11.3: Shooting photos for the panoramas at Nag el-Hamdulab in 2013.

technological improvements that involved networks and hardware during this period, helped VR to expand toward new fields of interest, including new sensorial achievements and new ways to interact with the experience based on social networking (Cipresso et al. 2018, Poetker 20195).

the data in company servers, preventing the client from accessing the RAW files and making changes. This was incompatible with one of our core goals, namely keeping the tour updated overtime. Lastly, the Matterport was more expensive than the AKAP could afford.

Before explaining our rationale in choosing 3D Vista, it is worth presenting one viable alternative. This system is Matterport, a combined hardware/software solution able to record 360 photos and 3D scans simultaneously. Together with an online service that offers data storage and processing, the Matterport creates attractive, functional, and ready-to-go tours and provides helpful graphic features, such as navigable 3D space that enables a very realistic walk-through effect (Chang et al. 2017). However, a few features did not meet the requirements of our project. Firstly, the Matterport device can only work indoors6 and Hamdulab is a very wide outdoor area. Secondly, the Matterport system stores and processes all

11.5 Where is the data coming from? The Aswan – Kom Ombo Archaeological Project has developed its own system to record and process archaeological data. Since 2009 it has used digital technologies to integrate and improve the documentation of archaeological sites and artefacts (Curci et al. 2012). When the Ministry of Tourism and Antiquities banned the use of plastic sheets in 2011, it increased the focus on the practices to record rock art. Most of the data that we used in our tour was not created specifically for that purpose, but for several other reasons over the multiple field seasons. This is significant not only to understand the potential of VR as a mediatic product but also as a means to combine, organise, store, and use heterogeneous datasets.

 We found interesting the overview/summary published online by Bridget Poetker for G2, the world’s largest tech marketplace, where she also highlights the commonly accepted but maybe not proper expression that VR is an ‘emerging technology’. https://www.g2.com/articles/history-of-virtual-reality. 6  The Matterport 3D capture system Pro2 can also be replaced by the Leica BLK360 3D scanner, a more expensive device that must be purchased from a third-party company 5

Overtime AKAP, as most of other projects, has collected a substantial amount of information in many formats, manual and electronic, published and unpublished, graphic and textual, etc. The NH1 folder itself is more than 90 gigabytes large, and the data was produced in about 139

Alberto Urcia, Alessia Brucato, Maria C. Gatto, Antonio Curci ten years of research. If we look at the AKAP archive in general, we notice a notable change in folder size and file typology, starting in 2010. After 3D imaging (mainly stereo-photogrammetry and Structure from Motion) began to replace our older recording methods, the number of pictures drastically increased, as well the number of heavy files, such as 3D models and videos. This, of course, motivated the consideration of new systems to manage our data.

medium format cameras) could increase the resolution of final layouts. We had to answer a series of questions to pick the best shooting procedure: what is the scene’s lighting conditions? Do we have to record the sky and ground floor? What are the limits of our equipment? Will scenes require switching between automatic and manual focus (as in the case of clean sky or homogeneous coloured surfaces)? Will the scene have possible moving subjects? Will the scene be impacted by high contrast areas that could require advanced exposure settings? These questions are just the most standard, but they present a sense of the technical scenario confronting any researcher approaching a 360°shooting project.9

11.5.1 Planning the tour The good satellite imagery coverage available for this geographic region helped to preliminarily plan the fieldwork and optimise timing and efforts. Being onsite during this phase of work made it easier to design a possible trajectory on which to record the viewpoints and to organise the “walk-through” effect in the tour (see chapter 7.3). Considering the equipment available, time, and other logistic matters, we established a total of 15 locations that offered sufficient graphic continuity while virtually transitioning between them (see the Floorplan in figure 11.4b).

To reduce as much lens distortion as possible, optical deformation (i.e., bulge of straight linear elements) and errors in the stitching phase, it was important to determine the optical centre of our lens. This must be positioned on the projection of the (vertical) axes passing from the rotation centre of the head once mounted on the tripod. The Panosaurus 2.0 allows the operator to shift the position of the camera forward or backward along its horizontal arm until the two centres match perfectly (Johnson 2008; See also Panosaurus 2.0 user manual).

11.5.2 Recording the panoramas As we mentioned, the acquisition of the panoramas was made during the 2013 campaign, five years prior to the idea to build this virtual tour. At that time, the project was still mainly focused on 3D and topographic recording of the sites and the 360° panoramas were thought just to provide additional documentation of the landscape.7 Jacobs (2004) clearly shows that 360° photography and related displayers were already quite developed in 2004 when, after a successful period in Real Estate and Interior Design, they finally started making their first steps into archaeology. Considering how much the site suffered in terms of preservation and the risk of new threats, we thought it was a good idea to record and save NH1 rock art in relationship with the landscape using additional techniques. Although more advanced devices and software were already available, in 2013 we accomplished our goal using a simple but accurate manually operated panoramic head called Panosaurus 2.0,8 combined with a Benro aluminium tripod and a Canon EOS 500D with an 18 mm lens. This was a cheap but very effective setup that worked well in that situation (see figure 11.3). The biggest differences that we noticed after recent experiences using newer cutting-edge automatic/motorised gears are photo acquisition/stitching time and costs. In terms of quality and accuracy the results are quite the same, although RAW photos taken with larger sensors (i.e., 36 mm full frame or

At this point we calculated the best rotation angle on which to turn the camera each time to ensure an overlap of at least 40 per cent between the consecutive shots. We have done this for both vertical and horizontal rotations. For the 18 mm lens, 20 degrees horizontally (for a total of 18 shots per row) and 30 degrees vertically (repeated four times to obtain four inclinations = rows) worked well. This way each panorama was composed of 72 photos. Using an IR shutter to reduce unnecessary contacts with the camera, we took all the photos following the aforementioned schema for all the 15 Viewpoints. For each viewpoint we also recorded its topographic coordinate using a handheld GPS device, to position the relative Hotspot properly on the Floorplan (see chapter 7.2). It took about 15 minutes with our equipment to complete each photographic session and about the entire working day to complete the entire site. 11.5.3 Stitching the panoramas and preparing the contents To stitch the photos together and create the panoramas we used the Stitcher V4 software, produced by 3D Vista,10 a powerful solution that offers a solid automatised process to create good quality panoramas. The interface includes tools to manually control and modify parameters in case the result from the automatic process is not as expected.

 The 3D recording of the landscape was done during the 2010-2011 campaigns. Unfortunately, UAVs were not yet available and the device we had on board (a Topcon Imaging Station) was not suitable to create high resolution and realistic 3D models of such extended areas. 8   Unfortunately, the production of Panosaurus products is discontinued. Some models can still be found on the used market, but people are already opting for similar alternatives such the Nodal Ninja products produced by Fanotec https://www.fanotec.com/. 7

  For a more complete overview on Panorama acquisition and processing, see Highton 2010 and Jacob 2004. 10   https://www.3dvista.com/en/products/stitcher. This software is included without additional costs when purchasing a Virtual Tour Pro licence. 9

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The site of Nag el-Hamdulab in 360° We experienced several cases where the software was unable to layout the panoramas properly, requiring manual retouching with additional software (Adobe Photoshop). These problems were mostly caused by the user, the software or by something that happened in the scene during the acquisition:

1a) The tour tutorial; 1b) The project; 1c) The site, 1d) The floorplan and 1d) The acknowledgments and credits. All these are always accessible from the Dashboard. The second section instead includes all the information pertaining to the rock art. This is subdivided into nine main containers called ‘Locations’ (delimited areas of the wadi with at least one panel with glyphs) and 18 Panels (delimited areas of rock surface with at least one glyph incised) both connected to various sub-containers with media, text and links (Contents).

• overexposed or burned areas that failed to be properly blended • mismatches between linear elements passing from areas with higher distortion • software misinterpretation of similar or repeating subjects (patterned surfaces) • too much or insufficient redundancy in the upper and lower areas (sky and ground level) • holes left by the area occupied by the tripod

To identify Locations and Panels in the background, we created other Hotspots, icons and polygons (see figure 11.4), and we positioned them exactly where the subject they represent appears on the Panorama. Similarly, we created customised icons for all the contents, differentiated by category: a) Modern photos, b) Historic photos, c) Videos, d) Drawings, e) 3D models, f) Extra documentation and g) Published material.

Overtime, working on other similar projects, we noticed that these stitching failures are common when lowcost equipment is involved or when users skip technical caution to speed up the recording process. Such conditions produce acceptable results but with a lack of accuracy that requires extra time in post processing.11 These problems could be avoided, for example, by using one-shot 360° cameras or motorised heads.12

All NH1 tour contents correspond to what we call ‘Dataset’ and are organised by typology of files as summarised in Table 11.1. Although Virtual Tour Pro offers a rich library of default customization items, we opted to create our own set of graphic contents to be consistent with the style of our project. Using external applications (Adobe Photoshop and Illustrator) we drew a series of hotspots (buttons, symbols, icons, logo, shapes) that, once loaded (mostly as .PNG format), will enable users to interact with the tour. By clicking on them, the user can run pre-assigned scripts that prompt commands and other actions useful to properly interact with the tour and the interface. In some cases, it was necessary to draw custom shapes directly on the panoramas to delimitate areas or subjects and have them work as hotspots. Each graphic entity, summarised in a Key list (Figure 11.6), indicates a specific typology of content in the tour. Beside hotspots, we also designed our own swabs (orange circles indicating the name of the viewpoint and the North direction) to patch the floor gaps left by the tripod.

Another important phase of the workflow, fundamental and often time consuming, is retrieving and editing the data that is coming from external sources that must be imported into the tour and connected to the panoramas. 11.6 Nag el-Hamdulab Virtual Tour and its architecture We decided to design NH1’s tour as a sort of very simple web page. All the information can be accessed by interacting in two ways (Figure 11.4): The Hotspots linked to the panoramas and the Dashboard, that always overlays the panoramas in the lower part of the screen. By loading the tour URL, a cover page will prompt first, showing a welcome message together with two buttons that direct respectively into the tour or to AKAP’s official website. Once inside the tour, the first panorama starts facing East, toward the village and the Nile. This should facilitate the user orienting himself according to the local topography.

11.7 The engine of NH1 experience: 3D Vista and Virtual Tour Pro (VTP) The tour was built using third-party software produced by 3D Vista (https://www.3dvista.com/). 3D Vista products became more popular from 2018, launching the new versions of Stitcher V4 (see the previous paragraph) and Virtual Tour Pro,13 which have become, in our opinion, the best alternatives currently available. These are not designed for developers: user-friendly interfaces enable any user with basic computer knowledge to start working and create a tour (Figure 11.7).

The information is organised in two main sections: 1) General information and 2) Rock art data. Everything is connected using a simple hierarchical relational network (Figure 11.5) based on ‘type of content’. The first section includes five subsections (also called ‘containers’) dedicated to what is not directly related to the rock art:

In this section we will focus on Virtual Tour Pro, the ‘engine’ of our VR tour. Its interface includes a series of tabs to navigate

  For an overview of the most common problems due to distortions and basic methods to solve them see Jacobs 2004, 37-52. 12   A good One-Shot Camera solution currently available on the market is the Ricoh Teta series (https://theta360.com/en/). A motorised head instead that could be suggested is the Gigapan Epic Pro (https://gigapan. com/cms/shop/epic-pro). 11

 https://www.3dvista.com/en/products/virtualtour. 3D Vista offers discounted plans for Educational and Non-Profitable institutions. 13

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Figure 11.4: NH1 main user interface. A) Container for the Rock Art contents; B) The Floorplan.

Figure 11.5: NH1 tour architecture.

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The site of Nag el-Hamdulab in 360° Table 11.1: Types of data managed into or through 3D Vista Text

Images

Video

Maps

Links

3D models

Vectors

Instructional

Old photos

Floorplans

Linked text

New photos

Linked buttons

Bibliography

Drawings

Satellite (E-link)

Linked 3D models

Buttons

Archaeological

Tutorials Documentary Renderings

Annotations

Maps

Captions

Aerial

Youtube Interviews

GIS (E-link)

Figure 11.6: The tutorial and Key section.

Figure 11.7: Virtual Tour Pro working interface.

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Commands

Alberto Urcia, Alessia Brucato, Maria C. Gatto, Antonio Curci Table 11.2: File format management into Virtual Tour Pro

between eight main sections (Main Menu) that basically correspond to the application’s operational workflow: My Tour, Skin, Panoramas, Photo Albums, Videos, 360 Videos, Floorplans and Publish. Within each section, a sub-menu of options to manage and edit contents, graphics, and actions, appears under the main menu. The column on the right is an additional space dedicated to control parameters and operate advanced options and tools. The software allows the user to operate using macro functions through specific toolbars, but it also enables more advanced tasks by running java-scripts into the Skin panel. VTP is able to read and manage the most common file formats that must be imported or linked in order to create ‘contents’ (Table 11.2). 11.7.1 Managing the panoramas Loading at least one panorama is a minimum requirement to be able to create a ‘New Project’. A wizard procedure helps select and customise the Skin (foreground graphic) with available default templates and create a background graphic (static or dynamic) with the following options: Create Panorama (it creates a panorama from scratch), Import Panorama (previously stitched photo), Import Video 360 (option available from the 2020 release). Once loaded, they can all be displayed and customised within the Panorama’s tab. Common parameters that can be modified include, for instance, the display quality (the image resolution), the spherical deformation (to be selected according to the used stitching algorithm), zoom limit (in and out) and the vertical/horizontal angles of visualisation (in other words the horizon and orientation of the spheric space). If we think about ‘number of panoramas’, we can say that what makes a difference is not how many Viewpoints are loaded but rather, the distance between them that will visibly improve the walking-through transition and so the immersivity of the tour.

CONTENT

FORMAT

ENGINE

Images

.jpg; .png; .tiff

VTP+HTML5

Video

.mp4

VTP

Audio

.mp3

VTP

3D Models

.obj; .dae; .stl;

Sketchfab

Maps

.jpg; .png; .tiff

VTP

Text

.txt

VTP

Linked media

URL; Embedded codes

Third-party software

11.7.3 Interacting with the tour: The Skin section It was very helpful, before setting up the Skin section, to have a good plan for arranging the various graphic layouts that compose the interface and their functional hierarchy. This is important to avoid malfunctions or misbehaviours while interacting with the interface. The central area of this section has a window that simulates the tour, as a sort of preview. There are many items available from the Skin’s submenu to add and customise14. All their options and parameters can be edited and controlled from the Properties column on the right. A very interesting option available in the Skin section, is the possibility to preset the tour layout for different size devices, such smartphones, tablets, or laptops. For each visualisation selected and loaded, the software creates an independent copy of the General visualisation so that all the modifications made in one will not affect the other. We suggest waiting until the Skin is fully completed in the General visualisation before starting working on other layout formats, to avoid repeating work or needing to redo the changes for each visualisation created (three in our example).

Once all the panoramic images are uploaded and calibrated it is possible to upload all the files that will fill this nicely decorated but still ‘empty container’. 11.7.2 Floorplan settings

The Skin that we created for the NH1 tour is quite minimal, on purpose, in order to offer a more realistic/natural way to display the landscape. In the foreground, the user will only see a few buttons that are part of the dashboard, located in the lower part of the screen and always visible. By clicking on them, popup windows will enable the following items (see figure 11.4): from the left side, Full screen mode; the Tutorial and Key page; the general information page on AKAP; the general information page on Nag el-Hamdulab site; the button that activates the gyroscope; the Floor Plan; the credits and acknowledgment page and the Navigation board.

A powerful section of 3D Vista VTP is the Floorplan, a term borrowed from the real estate industry that could be translated, in our case study, simply as ‘Map’. Floorplans are used in VR to navigate in the digital space without getting lost. Any image can be turned into an interactive map and used to navigate within the tour. This is possible by placing hotspots on the Floorplan and by clicking them to be ‘teleported’ onto that specific location. In our case, the hotspots that we created on the NH1 plan, correspond to our Viewpoints. At the same time, while moving the panorama (or the head if the user is wearing headsets), a small radar symbol can be enabled to indicate on the map which direction we are looking in that moment. The result of all these settings can be previewed into the Skin panel or in the final layout. We created our Floorplan using a simple black-and-white satellite image taken from Google Earth and edited in Photoshop (see figure 11.4).

 The ones available so far are: Viewer, Floor Plan, Container, Web Frame, Label, Text, Image, Button, Icon Button, Close button, Progress bar, Tab, Dropdown, Thumb list, Misc. 14

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The site of Nag el-Hamdulab in 360° 11.8 Is VR an advantageous tool for rock art studies?

On the background (the panoramas), we placed several different icons according to the function they have and what they represent. All these icons work as buttons that can be used to move around the virtual site (walk through and teleport options) or to open and display contents (media and info) loaded into sub-containers that function as popup windows (i.e., a panel of rock art). The sub-containers may include additional buttons to open sub-contents that will appear into a sub-window that will display whatever info or media is available for that panel (see figure 11.4).

To explain why, in our opinion, VR can provide a significant positive impact on epigraphic studies and, in particular, rock art sites, we must focus on the relationship between three aspects of this technology. First, it is important to recognise VRs potential as a means to communicate knowledge from specialists to the public at large. An increasing demand for Virtual Reality systems has driven their rapid uptake by museums in order to facilitate access to collections. This trend has expanded even more rapidly over the course of the COVID-19 pandemic (Ren and Chen 2020; El-Said and Aziz 2021) and has expanded rapidly beyond museums. Virtual tours that use Cultural Heritage content are growing fast in the field of education along with so-called “Serious Games’’ that are specifically made for teaching purposes (Mortara et al. 2014; Buscemi et al. 2020). Other uses of Virtual Reality have also developed simultaneously, with commercial games such as, e.g., Assassin’s Creed: Origins, Call of Duty, Age of Mythology, etc increasingly driving development and relying on this technology as a main selling point. It would be interesting to have an updated study on the impact of VR in the field of education and see how much this has changed since 2009, when the effects were still uncertain (Tost and Economou 2009), alongside this increasing commercialization.

11.7.4 Managing external contents: 3D models and Web URLs 3D Vista Pro does not offer, so far, to embed certain types of media directly into the project file. The developers opted for a web-based external archiviation of certain content that would increase too much the weight of the project, enhancing risks of malfunctions and costs. The way to solve this is by embedding only the links to the contents that will be displayed in the tour using windows that can translate HTML5 code into graphics as a web portal. The advantages in terms of browsing performances and workload optimization are enough to justify having a tour that cannot be fully accessed offline. In our case study we used Sketchfab to connect our 3D models (https://sketchfab.com). Sketchfab is a well-known third-party online platform that offers several ways to store, manage, display, and share 3D contents. What is important for us here is the possibility to create links to the 3D models that can be embedded into VTP (Figure 11.8). It is worth noting that, with this system, whatever needs to be changed in the linked model can only be done either on Sketchfab or on the source file.

The second aspect is related to how useful and effective VR is becoming as an innovative tool for research. Working on the NH1 tour we personally noticed the advantages of having a system that keeps data combined and allows users to graphically interact with the data in a flexible manner. Checking what was missing and often desired by researchers, especially when digital technologies started increasingly replacing older recording methods, we kept getting the same answer: smart and effective systems able to keep large numbers and types of data connected without losing relationships and visibility between them and their spatial context. If we look at the quantity of information that a typical archaeological project now produces for each site, it is quite impressive: hundreds of gigabytes of data that includes text, maps, drawings, images, field notes, databases, 3D models, audio/video recordings, and websites. So, what can we do to make all this stored data look like ‘one site’? In our opinion this is pretty much solved by NH1. A VR tour based either on 360 photography or on 3D modelled environments, can be seen as a ‘magic sphere’ able to contain, at the same time, all those files and documents that we commonly archive in different locations, such as drawers, hard drives, software, servers, books, etc. But the single location is not the only wonder. The sphere is in fact able to graphically translate and display all the contents therein, relationally connected between them and topographically linked to their original location. Additionally, it is offering an easy way to interact with all of the data in real time and in a safe controlled manner.

11.7.5 Testing and Publishing Virtual Tour Pro offers a low-resolution preview tool to display the result of what has been programmed in a browser window. This helps to enable a preliminary check of the tour, after which the designer can change or correct parts before exporting the result in the sharable formats. This is important because the exportation process can be time consuming. Once everything works well in the preview, it is time to step into the Publish section and produce the “Built” file. This file or group of files can be uploaded in servers or domain for online publication15 (i.e., HTML5) or saved into local drives to be run offline (i.e. .exe). Furthermore, VTP offers to convert the tour in a video or in a Google Street View file. All these options work on desktop and laptop computers, as well as on mobile devices equipped with gyroscopic sensors, such as smartphones, tablets and headsets. Wearing a headset also adds the possibility of experiencing the tour in an immersive manner.

  3DVista offers its own hosting cloud service if needed (https:// www.3dvista.com/en/products/hosting/). 15

This is an exciting step forward, especially for disciplines 145

Alberto Urcia, Alessia Brucato, Maria C. Gatto, Antonio Curci

Figure 11.8: Embedded 3D model run from Sketchfab into VTP.

such as epigraphy, characterised by large quantities of qualitative data. Unfortunately, a Virtual Reality Tour 360 (VRT360) cannot be produced automatically (yet!), and it still requires quite a lot of programming work and coordination between the team members involved in the study of the site and project development.

not prevent data from being re-edited, updated, queried, and shared as needed. VR tours can also be a great support to educational and teaching purposes, even though, in our opinion VR technologies should not be intended to replace standard methods but rather support them. For the public, and consumers of cultural heritage research, VR is an important alternative way to be a visitor to a site. Regardless of the conditions of the original, in the present, having the opportunity to get a VR experience can offer a base of preserved knowledge that can be easily accessed and completed quickly.

This last part is important and necessary to build the section aimed at helping the user to navigate the tour independently, as if the visitor was walking into a real site. While planning we had to consider, of course, what the goal of our tour is, and this determines the way to curate the contents according to the needs of the recipient.

The NH1 tour already includes many features that are positively impacting the site and its preservation. This is a starting point for future developments of the tour itself and of the role of VR within a wider perspective of its application in a larger scale and systematic manner. An upcoming option that will be available in the NH1 tour is an increase in the ways that visitors can access the experience. First, we will enable the possibility to select multiple languages, including Arabic and Italian as the first two options. Then, we will customise the tour for different types of visitors, for example experts, amateurs, children, and students. Upon signing up to the AKAP website, these different categories of users will be provided with selective access privileges to better control and protect the data, and guide learning and interaction16. Another goal

Having part of the team who worked on NH1 tour that have never been on site before showed us how powerful VR could be also for remote learning. Alessia Brucato, one of the authors of this chapter, said «The first time at Nag el-Hamdulab felt like I knew the place and I was able to orient myself as if I had already been there several times. By navigating into the virtual tour, the image of the site and its rock art was built involuntarily into my brain and it was easy to recall that once in front of the original». 11.9 Conclusions and future development The development of Virtual Reality Tour 360, like the example provided here from Nag el- Hamdulab, provides two critical benefits to researchers and the public. For those who are working in cultural heritage, VRT360 is a new and effective system to keep all the information from a site together, logically connected, and graphically visible and accessible. At the same time, this type of dataset will

 Especially if third-party, copy-righted, or unpublished data will be included 16

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The site of Nag el-Hamdulab in 360° Introduction to Satellite Remote Sensing. Atmosphere, Ocean, Cryosphere and Land Applications, edited by W. Emery and Camps, A., 565-96. Elsevier, 2017. [DOI: https://doi.org/10.1016/B978-0-12-8092545.00007-5].

is to define various stages of experiences17 to consider a wider number of sites, including those with a secondary importance, into one or multiple VRT360 models. The rapid pace of recent developments in the Virtual Reality industry suggests VR tours are likely to become a standard technique to be included in research workflows.

Gatto, M.C., Hendrickx, S., Roma, S. and Zampetti, D. “Rock art in West Bank Aswan and Wadi Abu Subeira.” Archéo-Nil 19 (2009): 149-66.

The benefits are already visible to us and we are quite sure we are not alone in this. We are positive that Virtual Reality will continue to grow in importance within the field and will become well recognised and widely employed as a means to explore and discover the wonders of cultural heritage, and rock art in particular, all over the world.

Gatto, M.C. and Curci, A. “Rock art of the First Nile Cataract region”. In Current Research in the Rock Art of the Eastern Sahara, In Memory of Dirk Huyge (1957-2018), edited by M. C. Gatto, P. Medici, P. L. Polkowski, F. Förster, and H. Riemer. Oxford: Archaeopress. Forthcoming.

Nag el-Hamdulab Virtual Tour is finally accessible on the web at the following address: https://www.akapegypt.org

Hendrickx S. and Gatto, M. C. “A rediscovered Late Predynastic-Early Dynastic royal scene from Gharb Aswan”. Sahara 20 (2009): 7-10.

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Lippiello, L. Landscapes of Ancient Egyptian Religion: Rock Art as Indicator for Formal Ritual Spaces during the Formative Stage of the Egyptian State, Unpublished PhD dissertation, Yale University, Dept. of Near Eastern Languages and Civilizations, USA. 2012.

De Morgan, J., Bouriant, U., Legran, G., Jéquier, G. and Barsanti, A. Catalogue des monuments et inscriptions de l’Égypte antique. Première série. Haute Égypte. Tome premier. De la frontière de Nubie à Kom Ombo. Vienne: Adolphe Holzhausen, 1894.

Lippiello, L. and Gatto, M.C. “Intra-site chronology and palaeo-environmental reconstruction at Khor Abu Subeira South (Aswan, Egypt)”. In The Sign of Which Times? Chronological and Palaeoenvironmental Issues in the Rock Art of North Africa, edited by D. Huyge, F. Van Noten and D. Swinne, 269-93. Brussels: Royal Academy for Overseas Sciences, 2012.

El-Said, O. and Aziz, H. “Virtual Tours a Means to an End: An Analysis of Virtual Tours’ Role in Tourism Recovery Post COVID-19.” Journal of Travel Research (2021): 1-21. [DOI: 10.1177/0047287521997567]. Emery, W. and Camps, A. “Chapter 7 - Orbital Mechanics, Image Navigation, and Cartographic Projections”. In

Mazuryk, T. and Gervautz, M. Virtual Reality. History, Applications, Technology and Future, Institute of Computer Graphics, Vienna University of Technology, Austria. https://www.cg.tuwien.ac.at/research/ publications/1996/mazuryk-1996-VRH/TR-186-2-9606Paper.pdf (accessed 08 November 2021). 1999.

  Not all the rock art sites have the same number of drawings, size, importance, or preservation. Therefore, also the level of representation could be calibrated accordingly, as well as the VR experience. A secondary importance should not prevent the site from being properly documented. 17

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A R C HA E O L O G Y O F P R E H I S T O R I C A RT BA R I N T E RNATIONAL SERIES 3098 ‘The wide geographic scope of the proposed volume is particularly interesting, as well as the application of the diverse range of technologies to a great diversity of rock art and context types.’ Dr Joana Valdez-Tullett, Wessex Archaeology ‘This is a very worthwhile approach to the digital recording of rock art. This topic has been addressed by a number of publications, but none cover such a wide scope as this book.’ Professor Ramón Fábregas Valcarce, Universidade de Santiago de Compostela

Rock Art Research in the Digital Era covers the research presented at the 20th International Rock Art Congress (IFRAO) held in Darfo Boario Terme, Valcamonica (Italy), from 29 August - 2 September 2018. With a broad understanding of digital archaeology, a diverse range of specialists demonstrate how digital technologies can benefit the study of rock art in a variety of contexts. Digital methods and 3D modelling are significantly changing the field of rock art documentation and interpretation, with new approaches that allow us to make eroded rock art panels more visible, especially in cases where the human eye or a raking light is ineffective. Using numerous case studies, this book illustrates how cutting-edge methodologies are integrated within 3D modelling workflows, and how these can manage and disseminate the results to the public in an interactive way. Miguel Carrero-Pazos is a Lecturer in prehistory at the University of Oviedo. He is a specialist in computationally informed landscape archaeology, and his research focuses on the application of GIS and spatial statistics to model monumental landscapes. Rebecca Döhl is a Lecturer at the Institute of Archaeology who specialises in rock art research, landscape archaeology, GIS, 3D photogrammetry, and Digital Humanities. Since 2016, she has been the project coordinator for Corpus of Ancient Egyptian Multimodal Communication (Humboldt University of Berlin). Julian Jansen van Rensburg, who works for the Centre for Middle Eastern Plants, is the world’s leading expert on the cultural heritage of Soqotra, and over the last 20 years he has been involved in numerous research projects and expeditions on the island. Paolo Medici is the Excavation Director at the Centro Camuno di Studi Preistorici. In the 2020, he founded ArchExperience, which focuses on experimental archaeology. Alia Vázquez Martínez is a Postdoctoral Researcher at the University of Santiago de Compostela and the University of Alcalá. She is a specialist in the application of computer techniques for the documentation and study of rock art in Northwest Iberia. Contributors: Márcio Amaral, Rogério Andrade, Xavier Barros Pereira, Cinzia Bettineschi, Marcos Eugênio Brito de Castro, Alessia Brucato, Laura Burigana, Marta Sara Cavallini, Antonio Curci, Manoel Fabiano da Silva Santos, Armando De Guio, Claide de Paula Moraes, Steve Dickinson, Miguel Espino Villarreal, Emanuela Faresin, Gianni Furiassi, Maria C. Gatto, Luigi Magnini, Carla Mannu, Vanesa Mariño Calvo, Alberto Marretta, Eloy Martínez Soto, Angelo Martinotti, Levemilson Mendonça “Lei’’ da Silva, Paula Morgado, Alexandre PazCamaño, Carlos Augusto Palheta Barbosa, Radosław Palonka, Agustina Papú, Leonor Rocha, Giuseppe Salemi, Filippo Stampanoni Bassi, Giuseppa Tanda, Alberto Urcia, Raoni BM Valle, Jaime Xamen Wai Wai, Bolesław Zych

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