A Geographic Information System for the documentation of medieval and modern fortifications.The district of "Castello" in Cagliari

This paper shows some results of the documentation of the medieval and modern walls in the district of Castello in Cagliari. The area appears today as a result of urban transformation and project interventions that over the centuries have changed the design and urban landscape. This system determines a complex structure of the survey, that, set on the graphical analysis of documents and on the survey of existing structures, is supported by historical and archaeological disciplines and "non-destructive diagnostics investigations". The "place" where collect data from the studies conducted in the context of the different scientific areas is represented by a geo-referenced database, which allows to an easy management of information and the ability to overlay and display the different layers of information. Identified the cartographic base in a recent photogrammetric survey, the work is proceeded with the digitalization of historical cadastral maps, graphical analysis of the projects and the survey of historical military structures in the south area of Castello. The survey starts a process aimed to creating a database that can be implemented and became functional to identify the archaeological risk and a prior assessment tool to any project action.