RELIABILITY OF DTMS OBTAINED WITH MOBILE FAST SURVEYS TECHNIQUES

The contribution addresses the issue of the integrated survey aimed at three-dimensional modeling for the documentation of different types of terrain through the analysis of two case studies located in the province of Pavia - Italy. The techniques of aerial photogrammetric acquisition SfM (UAVs), Terrestrial Laser Scanner (TLS) and Mobile (MLS) are now consolidated and widely used, managing to meet the needs of documentation of land levelling, monitoring, and analysis of landslide volumes. The two case studies present difficulties due to a strong inclination of the land and extensive presence of vegetation in the first case and to a strong presence of agricultural canalizations in the second case. The data processing phase focused on the comparison between MLS and close-range photogrammetry, while the acquisitions from TLS were used as control data. This acquisition method allows avoiding the process of approximation and reconstruction of the DTM under the vegetation, ensuring the correctness of the data relating to the ground course. The database allows the generation of highly reliable DTMs using specific point cloud modeling and processing software. Fast survey instruments are ideal in large areas or in hilly areas where sub-vertical sections and covered by vegetation are often present, difficult to detect only with close-range photogrammetry.