Drones in archaeology : a comparison of unmanned aerial vehicle imaging with conventional documentation of excavation

Abstract

Over the last few decades, archaeologists begun to recognise the value of Unmanned Aerial Vehicles (UAVs), commonly known as drones. UAVs begun to be employed for different archaeological purposes such as site reconnaissance, surveying, mapping and, recently, for fieldwork documentation. Given the growing interest towards the latter application, this research compares and contrasts the techniques and outcomes of both UAV photogrammetry and archaeological drawing, in order to analyse the efficiency and accuracy of these two documentation methods. The data compilation of this study entailed fieldwork which was carried out in July 2018 at the Żejtun Roman Villa, in South-East Malta. The photographs were taken with a DJI Spark UAV and processed employing Agisoft PhotoScan Pro to create highly accurate 3D models, orthophotomosaics and digital elevation models (DEMs). The digitally processed data was then compared with hand-drawn plan and elevation drawings, showing almost matching results. The results have shown the potential of digital photogrammetry for the purpose of archaeological documentation and its complementarity to the conventional recording techniques. The remarkable advantages offered by UAV photogrammetry have shown speed of action on site, high data resolution and accuracy and 3D and chromatic rendering of the documentation. This study shows how UAV-based data allows the performance of a more efficient fieldwork and detailed documentation record. These advantages can result critical for certain archaeological contexts which are affected by time and cost restrictions, such as rescue archaeology. The scope of this research is found within two ongoing academic projects run by the Department of Classics and Archaeology of the University of Malta. These are the Żejtun Roman Villa Project – directed by Prof. Anthony Bonanno and Prof. Nicholas C. Vella and coordinated by Dr Maxine Anastasi – and the Low Altitude Remote Sensing Of Compact Sites (LARSOCS) – coordinated by Dr Ing. John Charles Betts.