Bologna’s lost and surviving towers: a GIS-based approach to cartographic heritage and historical documentation

This thesis explores the historical evolution of Bologna’s medieval towers by integrating archival research, historical cartography, and modern geospatial technologies. It addresses the challenge of reconstructing a fragmented urban past, in which many towers that once defined the city’s skyline have disappeared or undergone significant transformation. To overcome the limitations of traditional documentation, a Historical Geographic Information System (HGIS) was developed, enabling the spatial and temporal visualization of both existing and lost towers. The project involved the recovery of data from different documentation, the georeferencing of historical maps and photographs, the creation of a structured database containing detailed information for each tower, and the integration of these datasets within a GIS environment. The system allows users to see the location of the towers (many of which no longer exist) on historical maps, to filter and analyze the information concerning the towers based on different attributes, such as construction period, height, function, owner-ship, and current condition. This interactive platform cannot only support academic research but also broaden public engagement with the city’s urban history. By digitally reconnecting dispersed historical sources, the study can offer a more comprehensive understanding of Bologna’s built environment and its transformation over time, focusing on one of the symbols of the city. It demonstrates how digital cartographic methods can strengthen heritage studies, support preservation efforts, and provide new frameworks for interpreting the evolving relationship between space, memory, and identity in the historical city.