Time and Space in the History of Cities

This essay deals with the representation of cities focusing on their historical transformations and relying on digital scanning, 3D modeling and Augmented Reality (AR) technologies. The instances shown in it come from a project titled Visualizing Venice, an international multi-institutional cooperation now shifting to Visualizing Cities. The main challenge of Visualizing Cities is to digitally describe how cities – with their architectures – evolve and change over time using an interoperable 4D digital model linked to external sources, such as historic images. Experiencing the workflow of such a digital model a current lack of interoperability between CAD and GIS systems has emerged. This problem is particularly evident in the transition from digital scanning to a Building Information Model (BIM). This gap must be filled because a representational database, such as a 3D BIM model, helps researchers in representing architectural and urban history in all its phases. It makes the users able to control any kind of information: from recording the current state of an urban environment to the interpretation of historical records; from 3D reconstruction of data to their dissemination at different levels of complexity. This paper shows new methodologies in this field and, relating to historical data, attempts to answer also an important question: what kind of information can we get from paintings that show a city view? Representation methods based on perspective rules offer the opportunity to obtain scientific data on how to implement the BIM model correctly.