Geomatics approach to surveys for Late Antiquity buildings. The Episcopal Palace in Side, Turkey

Side is one of the best preserved cities of Antiquity in the historical Pamphylia area of Anatolia, current Antalya, Turkey. This archaeological site shows numerous standing structures and monuments spanning from the 7th century BC to the 12th century AD. The aerial and terrestrial survey conducted in 2016 was centred on the so called Episcopal Palace and the Fountain area with a total surveyed surface of 5,900 mq. The aim of the work was to analyse and recreate the existing structures in a 3D environment to help in later research questions like architectural features, building construction design and upgrades or location of the palace within the urban area. This paper intends to highlight the value of an accurate ground control point network to record an ancient urban site and its advantages when using CAD and GIS software. Moreover, it will also focus on the methodology used to capture the data used on the area of the Episcopal Palace to create an accurate 3D reconstruction of the remaining structures (with Structure from Motion) for further analysis and interpretations; merge classic survey methods (Total Station and Global Positioning Systems) with relatively new methodologies and hardware (Unmanned Aerial Vehicle); check and test the accuracy and the derived errors (data surveying gaps, traversing adjustments, coordinate and projection systems) that arise during post-processing (ellipsoid/geoid highs differences, noise reduction, fusion between datasets). Possible uses of the created/resulting data from the georeferenced point clouds, the model as a visual tool (orthophotos and 3D Mesh) for classic planning (elevations and sections) and its utility in a GIS environment (ArcScene) are also discussed. At the end of the paper report, some questions about the utility of the 3D reconstructions and models in Heritage as well as their utility for the archaeological record will be discussed.