The Buca di Spaccasasso cave is a prehistoric site located on a calcareous hill in The Regional Natural Park of Uccellina (Southern Tuscany, Italy) exploited during Eneolithic period for extracting cinnabar mineral and afterwords used as a funerary area. The excavation, conducted by Siena University, is actually focused on the funerary area characterized by secondary depositions densely overlaid . Many unarticulated fragmentary human bones were recovered; implementing an intrasite GIS is the right choice for interpreting the spatial relationships among finds; it is a powerful resource for studying the human activities as well the natural taphonomic process. Due to the peculiar archaeological context the traditional documentation maps are not effective tools to record the prehistoric site consequently we have tested photogrammetric elaboration. Hereby, we present the achievements of a work in progress project carried out in collaboration with the Interuniversity Research Centre for the Study and Promotion of Prehistoric Cultures, Technologies and Landscapes: we have implemented an intra-site GIS based on photogrammetry methodologies and a data model defined within a geodatabase.

The first goal of the photogrammetric application is the elaboration of 3d photorealistic restitution useful to obtain Digital Elevation Models and ortophotographs. Two different methodologies have been used, one based on the ERDAS IMAGINE LTS software, related to the concept of stereoscopic 3d restitution, the other one built up using some open source software developed on the bases of the multi vision scene reconstruction approach. 3D survey methodology and data recovery offer many advantages as far as concern data management: only the standard archaeological equipment, like a digital camera and a total station are part of the photogrammetric procedure, furthermore no technically trained personnel is needed and the procedure is not time consuming. This approach is an objective methodology to build up a realistic virtual reconstruction of the archaeological site, a way for instantly record the excavated archaeological context, equally effective for the soil characterization or for the finds. These sets of advantages must be related to other derived benefits, firstly the methodology fits well into the standard archaeological documentation procedure and allow us to carry on any kind of intra-site analysis.

The photogrammetric elaboration started in 2010 but, in an experimental phase, have been undertaken using photographs shot in the previous years not foreseeing a photogrammetric use. On the contrary, in order to develop the multi vision scene reconstruction approach, ad hoc photographs have been shot in 2011. The paper presents the comparison between the two methods adopted.

Pirisino D., Pizziolo G., Tessaro C., Volante N.