Geomatic and archival sciences applied to the Gregorian Cadastre of Bologna (Italy) for analysis and representation of the XIX century urban arrangement

The research focuses on the first establishment urban map of the nineteenth century Gregorian Cadastre of Bologna, kept today at the State Archives of the city. In this cadastral cartography the city is divided into some sectors; for each sector – unique case in the Gregorian Cadastre of the ancient Papal State – there are ground floor maps and maps for the floors above and below. The present study aims to analyse this peculiar cadastre using digital tools deriving from the integration of geomatic and archival skills. For some test-areas, a careful comparative consultation of the graphical information stored in the georeferenced maps and the writ-ten one in the related cadastral registers is performed; this allows 3D digital reconstruc-tions of the horizontal and vertical extent of the cadastral proprieties, and also thematic visualizations (e.g. according to owners, designed use, rent, etc.). This modern kind of representation allows a deep analysis of the complex nineteenth century arrangement of Bologna – still preserved in the ancient Gregorian Cadastre of the city –, highlighting some interesting aspects which otherwise would remain invisible. Thus, it turns to be a powerful tool of analysis for historians and city planners.