Archeologia dell'Architettura e Tecnologie per lo studio dell'insediamento umano medievale e post-medievale: le chiese rurali della bassa valle del Cedrino (Sardegna)

The aim of the research is the study of the ruins of many rural churches using some technologies, like 3D reliefs and a Geographic Information System (GIS). The churches are distributed throughout the lower valley of the Cedrino river, a hilly zone located in the central east coast of the island of Sardinia. The territory considers Loculi, Irgoli, Onifai, Galtellì, and Orosei municipalities. Most of these churches have been built during the medieval period, which makes it possible to estimate the human medieval settlement and to make a complete documentation of each church. Until today none of circa 20 sites has ever been investigated from an archaeological study. The research has provided a multi-scale study: from artefacts to landscape. The detailed scale has consisted in reading the masonry structures preserved and making an analytic documentation of buildings using 3D reliefs, where possible; the regional scale has been studied by storing data in a GIS and using those data for territorial analyses. The application of the three-dimensionality in the study of historical buildings is still relatively new. In order to resolve critical issues related to the methodology required in the archaeological-architectonic studies, further investigations are still necessary. In recent years, the development of 3D models in Archaeology and Cultural Heritage showed a growing trend, but in several cases during the data collection, as well as the historical analysis, archaeological knowledge is lacking. The information obtained from 3D models is limited to visualizations and virtual reconstruction. In this research, both the interior and the exterior of a selected sacred building have been surveyed by an integrated approach using a terrestrial laser scanner and photogrammetry. The use of multiple techniques was an essential requirement to produce complete 3D models of monuments, but also it was the best compromise among geometric resolution, costs, and time. Other monument have been documented by a photogrammetric approach called Structure from Motion. These models have been used to develop and verify the interpretations and archaeological analyses through the possibility to carry out geometric measurements, correlate surfaces with volumes, visualize the relation between inner and external walls. Finally, we have elaborated technical drawings for very high-precision documentation. All of the archaeological data collected during the surveys have been stored in the GIS to create an archive that can be connected to existing databases and implemented with data from different sources, such as information from surveys in remote-sensing landscapes archaeology and computerization of data from previous studies. The knowledge acquired will be the basis for the realization of preserving proposals and the enhancement of the cultural resource of “rural churches” involving and making local communities aware in its own history.