4D Geomatics Monitoring of a Quarry for the Calculation of Extracted Volumes by Tin and Grid Model: Contribute of UAV Photogrammetry

The purpose of this manuscript is to identify an appropriate survey technique and numerical method for the calculation of volumes extracted in a quarry. The impact of the TIN (Triangulated Irregular Network) and GRID method was evaluated firstly on a hypothetical stepped ground and one with a constant slope and, later, on a specific case study of a quarry of an important dimensions. In this case study, the survey at time to was performed by ALS (Airborne Laser Scanning) and at time t1 by the use of UAV (Unmanned Aerial Vehicle) photogrammetry. In the latter survey, the ease and speed in performing the 3D model by UAV photogrammetry was shown in the manuscript. Concerning the calculation of the volume over time, it has been shown how the TIN allows a calculation which is closer and more faithful to the reality than to the GRID model, in case the quarry conformation is in steps and, consequently, with important nearly vertical surfaces.