When there was no GIS system: Rediscovering archaeological researches of the 19th century through the use of the drone. The case study of Mount Siri (Anzi, Basilicata)

Modern archaeologists often find it difficult to identify the exact position on the field (and on the maps) of the finds brought to light during archaeological excavations, particularly those conducted before the second half of the 20th century. In these cases, in fact, they are obliged to record data and information on their GIS as being unable to locate the correct place, or even the area, of those ancient archaeological investigations. This inability to be precise creates several problems from a topographical point of view and negatively influences the archaeological reconstruction of specific territories or sites. Therefore, how is it possible to correctly locate and, as a result, mark on the map what was discovered or excavated in the recent past? One possible solution is the 3D reconstruction of a modern landscape through the use of the UAV technology and some derived applications, such as digital techniques based on Structure from Motion and Imaged-Based methodologies. The 3D model can be analyzed using the GIS system, and through the analysis of the micro-relief and aerial photos it is possible to use an important tool to locate past archaeological investigations. In this paper, we present the case study of Mount Siri (Anzi, Basilicata), the location of several important archaeological discoveries which were made during the 19th century.