Castelseprio archaeological site: LiDAR and GIS multiscale dataset supporting on-field investigation and enhancing landscape understanding

Castelseprio (in the Varese Province) is a site of exceptional value for the Lombardy Region (north Italy), both for its archaeological and monumental remains and its landscape and environmental context. This research, entitled “Castelseprio. Innovative technologies for the integrated management of enhancing interventions” was funded by Lombardy Region on the “Call for the promotion of enhancement interventions of the archaeological heritage and the UNESCO sites of Lombardy (2014)”. The call, presented by the Varese Province, saw the Politecnico di Milano - Department of Architecture and Urban Studies (DAStU, Laboratory “Techniques for the Conservation and Management of Architectural Heritage” (TeCMArcH) – as a research consultant for the creation of a specific Geographic Information System (GIS) project for the management of Castelseprio UNESCO site. Currently, the management and fruition of the site pose critical issues due to the historical events that have caused the loss of the physical unitarity between the upper area of the Castrum (with the ancient borgo and the Church of S. Maria foris portas) and the Torba complex (FAI – Fondo Ambiente Italiano) which formed the downstream limit of the fortified system. It is important to remark that Castelseprio was inscribed ten years ago in the UNESCO list as a component of the serial site “The Longobards in Italy. Places of the Power (568-774 A.D.)”, following the World Heritage Committee held its 35th session in Paris between June 19th and 29th 2011. The GIS has been organised into three territorial areas at different scale (Seprio Valley; Middle Olona Valley; Castelseprio Archaeological Area) using different information layers. Among the cartographic bases that have been used, there are historical, modern and contemporary maps, technical/thematic maps and aerial shots available. Other information layers have been added to these, such as the main elements of the geological/geomorphological interpretation of the terrain (paleo-beds, embankments, escarpments, etc.) and transformations related to environmental engineering interventions as well as hydrography. Of great use were also the elevation data through the definition of contour lines and the processing of a Digital Surface Model (DSM) and a Digital Terrain Model (DTM) of the entire area, based on the point cloud from the LiDAR flight. Being an archaeological site, the Information System has collected and georeferenced the data from past excavations acquired from bibliographic sources and archaeological reports, and from documents archived at the former Superintendency of Archaeology (topographical, excavations, photographic, drawings/reliefs archive, archival documents relating to the declarations of cultural interest). The analyses of historical maps have produced various outputs regarding the permanence of artifacts useful for a better understanding of the past landscape. These include the development and transformations of the historical itineraries and road network, religious and monastic buildings, the variation of land use destinations. A crucial thematic section for understanding the degrees of constraint was verifying the census of archaeological, architectural and landscape heritage regarding the current protection laws’ limitations. The GIS’s goal was to identify the archaeological potentiality of Castelseprio site and suggest actions for its future knowledge, management and fruition. To better communicate the results of the work carried out, as mentioned before, a dedicated GIS project has been developed to connect archaeological data, the relative graphic and photographic documentation, the scientific contents resulting from previous research and carried out with surveys during the project. The case study on Castelseprio is compliant with a comprehensive multidisciplinary approach addressing heritage, management and enhancing interventions. This approach combines theories, methods, tools from humanities and more techniques, ‘poly-tecniques’, providing new information and a general model that can be applied and replicated in other contexts.