THE DRONES ARE COMING. WHAT TO CHOOSE? LOW AND MEDIUM ALTITUDE AERIAL ARCHAEOLOGY ON LIMES TRANSALUTANUS.

Aerial archaeology has more than one century of tradition as a valuable research method. Like archaeology, the aerial reconnaissance is undergoing dynamic changes. The field must face the profound conceptual challenges raised by the evolving demands of archaeologists. In addition, aerial archaeology has to adapt its own methods in order to constantly incorporate new technologies such as: thermal vision, LiDAR and also advanced photogrammetry processing techniques. One of the greatest challenges and promising perspectives for evolution of the field is the arriving and rapidly spreading of small remote controlled aerial vehicles (UAVs – Unmanned Aerial Vehicles, known also as drones). However, a real development of the UAVs based aerial archaeology’s branch is conditioned by the availability of special tailored aerial vehicles for archaeologist’s needs. Unfortunately, the time has not yet come for this, while the major efforts in drones development is spent for aerial videography applications, surveillance and general entertainment. The implementation of a research project, dedicated to the longest built sector of the Roman limes in Dacia – Limes Transalutanus, represented for the authors a suitable occasion to assess the possibilities and limits of the large scale aerial archaeology based on UAVs. On the occasion there were tested two custom flying platforms and one commercial, multiple flight strategies and several processing algorithms. The linear nature and the extent of the site (basically a corridor of 157 km in length) called for distinct augmentation of equipment and survey workflows, with applicability in ‘corridor’ archaeological projects like those for highways and utilities networks.