EVALUATION OF CAMERA POSITIONS AND GROUND POINTS QUALITY IN A GNSS-NRTK BASED UAV SURVEY: PRELIMINARY RESULTS FROM A PRACTICAL TEST IN MORPHOLOGICAL VERY COMPLEX AREAS

Remotely Piloted Aircraft System was used for the engineering geological investigation of a marble mine area in Italy. High resolution images were processed by using SfM techniques for obtaining an accurate and detailed three-dimensional model of the area. Geological and geometrical information was used for a preliminary stability analysis with focus on investigating the contribution of potential rock bridges of two large blocks that pose a potential hazard issue for the workforce.