Digital terrain models determination by LIDAR technology : Po basin experimentation.

The recent LIDAR (Light Detection and Ranging) technology allows the construction of digital surface models, characterized by high resolution and precision. This technology is based on the scansion of the territory by laser telemeters, transported on board of dedicated airplanes, whose position and attitude are determined by means of GPS differential measurements and INS (Inertial Navigation System) measurements. However, it is often necessary to produce more refined digital models, whose construction requires the identification of the existing objects on the territory (vegetation, buildings, infrastructures). The present activity enters this context, since its aim is the construction of different kinds of digital models starting from LIDAR data survey produced in a unique Study edited by the Po River basin Authority. The filtering of such data has been carried out using a specific software implemented by the Laboratory of Geomatica of the Politecnico di Milano - Campus of Como -, suitably integrated by a semi-automatic procedure to build the different digital models required. The comparison between the computed digital terrain models in three test areas and those produced by the company that carried out the survey, has proved the substantial homogeneity of the results obtained by the two indipendent procedures, therefore a mutual validation of the procedures is guaranteed.