Topographic Interpretation and Quantification of Landslide Terrain Deformation Using Aerial Laser Measurement Data

Abstract

This study investigates the three-dimensional point cloud density necessary to quantify topography for prediction purposes. Index parameters have been collected for main scarps, flanks, scarplets, open cracks, and gravitational deformations, all of which are elements relevant to topographic interpretation. However, no comparison has been made between point density and qualitative terrain interpretation using aeronautical laser measurement methods and equipment. The study compares the point cloud acquisition efficiency of two different laser scanning systems, ALS and UAV, using seven different point cloud densities. In this paper, we examine the equipment, measurement accuracy, and topographically interpretable fine topography by applying the scanning systems at a rock fall site where measurements were taken 4 times. We found that a small cliff, 0.3 m tall, on a gentle slope can be detected at a point density of 1.0 point/m², and that detection of a 0.45 meter tall cliff on a steep slope is possible with a point density of 59 points/m².