The survey of the Lastra a Signa city walls (built between the second half of 1300 and the first half of 1400) is the result of three different survey campaigns made in 2006-2007-2008 and of the following data processing carried out as part of a Master thesis. It is a paradigmatic example of the overcoming of the concept of “survey as a mere measurement and graphic representation of a certain element”, by using a methodology protocol. At that time, survey operations became more complex because it was necessary to coordinate with a scientific basis the different survey phases: preliminary documentation, data taking with several instruments, data processing, data filing and cataloguing, two-dimensional representation of plans, cross-sections and elevations, wall decay interpretation and building materials analysis. The survey subject became a dynamic and ever-changing process, thanks to the introduction of digital survey and the availability of new technologies.

This paper describes the methodologies that were used in each different part of the survey campaign, of the data cataloguing operations and of the representation process, underlining the importance of the strict hierarchy of the acquired and rendered data. This hierarchy allowed to manage information obtained from topographic, laser, direct and photographic survey, and then to discretise, clean, georeference and make two-dimensional representations of the acquired data. Ultimately, it allowed creating a database that contains all these elements and ensures that the archived data can be updated in the future.