Application of automated photogrammetry and lighting techniques with GIS tools for visualisation and analysis of a slab with anthropomorphous reliefs

Extended Abstract: We present a methodological approach for the representation, visualisation and analysis of three-dimensional (3D) models of meaningful details in stone reliefs provided by digital documentation tools and subsequent processing. For this aim, anthropomorphous shapes engraved on a flat stone slab found in Sierra de Fontcalent (Alicante) are studied. The object under consideration was located near two archaeological sites, Cova del Fum–a cave with presence of the Chalcolithic material (López, 2010)–and the archaeological site of Fontcalent, with remains from different phases of occupation spanning from 7th-6thBC to the 20thcentury (Ximénez, 2012). In the last few years, the use of digital tools provided by new technologies and software development has left traditional work methodology behind (De Reu et al., 2014)while enabling the development of new approaches to both minimise heritage alteration and provide objective and accurate information (Lopez-Menchero, Marchante, Vincent, Cárdenas, & Onrubia, 2017). 3D documentation allows recording of cultural heritage at a reasonable cost with precision and quality through digital photography and SfM (Structure from Motion) photogrammetry with specialised software (De Reu et al., 2013). In this project, recording and documentation with digital photography and automated photogrammetric techniques are applied to the Fontcalent stone slab for its digitisation and subsequent 3D representation. From the resulting model, a two-folded line of study is obtained. On the one hand, a Digital Elevation Model (DEM) is generated to study the microtopographies of the stone with geographic analysis techniques provided by Geographic Information Systems (GIS) from different lighting conditions and surface reflections, which are calculated by hillshading or LRM (Local Relief Model) for the interpretation of the object (Carrero-Pazos, Vilas, Romaní, & Rodríguez, 2014;Gawior, Rutkiewicz, Malik & Wistuba, 2017).On the other hand, from both the 3D model and the point cloud, the study is completed with the application of the methods of analysis and visualisation based on the Morphological Residue Model (MRM) which stands out every single detail of the surface morphology of the object (Caninas, Pires, Henriques, & Chambino, 2016;Correia, Pires, & Sousa, 2014). Further visualisations are based on Reflectance Transformation Imaging (RTI) which provides different shadows and reflections over the object from the application of