The historical cities in transition in the global trend: some issues of architecture’s identity survey and representation of the genius loci

Among the problems of cities in transition there are also the strong imbalances deriving from the rapid transformations of the urban physiognomy caused from modernization and globalization, that put at risk especially the most delicate contexts, such as the historical cities and cultural heritage. Considering the historical cities as both memory’s witnesses and repositories of the potentiality of towns, the architectural survey (as the technical discipline providing the first knowledge of every transformation project), can be used to disclosure this potential updating its language; and it can be used to deeply understand the townscape as an analysis and a representation tool able to holistically describe both the material data and the immaterial elements of its genius loci, all inextricable factors of city’s identity and driver of sustainable development. The paper intends to present the analysis and representation approach of architectural “identity’s survey”, to discuss the architectural survey as an interpretation disclosing the potential of historical townscape and its propaedeutic function in the project of sustainable transformations, to explain the case study of Piazza San Pier Maggiore in Florence.