20 - 3D Reconstruction of Landslides for the Acquisition of Digital Databases and Monitoring Spatiotemporal Dynamics of Landslides Based on GIS Spatial Analysis and UAV Techniques

Abstract

In this study, the main steps that need to be taken to obtain the digital databases necessary for the three-dimensional (3D) reconstruction of landslides and the spatiotemporal monitoring based on unmanned aerial vehicle and spatial analysis geographic information system are presented. These include: presentation of work equipment, marking and measurement of the ground control points, flight plan achievement, aerophotographic image processing, obtaining digital databases representing 3D models [digital surface model and digital elevation model (DEM)], and comparative analysis of 3D databases to identify spatiotemporal changes. The databases representing the DEMs obtained as a result of two successive flights (May 2, 2015 and May 8, 2017) were compared using geoinformation software in order to obtain quantitative information on the landslide dynamics. The obtained quantitative data reveal negative differences of a maximum 1.63m (materialized by material displacements within the landslide body) identified spatially in the area of the main scarp and in the central-western part of the landslide and positive differences (materialized spatially by accumulation of slid material) of 1.32m spatially identified in the frontal and lateral-eastern side of the landslide as well as a 2.93m/year displacement which highlights its high dynamics. As a result of the quantitative analysis of the databases, negative and positive differences, as well as their spatial-territorial identification within the landslide body, a sliding displacement was identified in the direction of North-West (NV) and was calculated from 332 degrees in the case of the first measurement to 334 degrees in the case of the second measurement.