THE ETRUSCAN CITY GATES OF PERUGIA: GEOMATIC TECHNIQUES FOR THE DOCUMENTATION AND STUDY OF AN URBAN HISTORY HERITAGE

The Engineering Department of the University of Perugia and the Architecture Department of the University of Florence have started a research project on the ancient city gates of Perugia, belonging to the Etruscan city, dating between the third and second centuries b.C., and to the subsequent city wall completed in the twelfth century. In this paper, focus is placed on three Etruscan gates - Porta Eburnea (also called Porta della Mandorla), Porta Cornea and Porta Trasimena – which have in common profound Middle Age transformations and further significant context changes following the loss of function as defensive walls. Due to the decommissioning of this urban infrastructure, the gates have assumed a marginal role; nowadays they are almost completely absorbed by residential buildings, almost losing the memory of their origins and of the important Etruscan remains that are still preserved in the gates. Geomatic surveys on the three Etruscan gates were carried out by the Geomatics Laboratory of Perugia University in the frame of a research project financed by the Cassa di Risparmio di Perugia Foundation. The survey was carried out by means of a coordinated use of more Geomatic techniques: GNSS, Total Station, Terrestrial LIDAR and Digital Photogrammetry. From LIDAR and photogrammetry were derived dense point clouds, beside CAD plans, sections and elevations. The information acquired with these detailed surveys provide a completely new and accurate documentary evidence of the gates’ consistency, allowing to identify the actions and interventions that have changed their structure over time.