Rilievo architettonico remote sensing della Fortezza della Verruca sui Monti Pisani, Toscana (Italia)

The paper describes the digital survey project of the Verruca fortress, a medieval fortress built on top of one of the peaks of the Pisan Mountains to control the valley of the Arno river; the fortress was fortified in modern times by the Florentines and was visited by important architects such as Giuliano da Sangallo and Leonardo da Vinci. Today the fortress is in a state of ruin, and recently a summer fire caused the loss of the vegetation that had massified around the building, thus allowing to program the analysis of the walls of the fortress to deepen its construction history and state of material and structural conservation. The fortress survey project integrates range based, image based and UAV technologies, focusing attention on the methodologies used to ensure the high morphological reliability of the data obtained from the survey, in a very complex area to reach: in fact the position of the Verruca fortress does not present optimal landscape conditions to plan measurement operations. The three-dimensional model obtained by the drone, which is necessary for the reconstruction of reliable textures, has been verified to be reliable compared to the laser scanner model. Highly reliable drawings were obtained which are useful for analyzing the state of conservation of the architecture; thanks to the use of the drone it was possible to measure points that were not accessible until now. The results of the survey made it possible to reconstruct graphical drawings that made it possible to deepen the architectural and historical analyzes on the fortress.