Comparison of Terrestrial Laser Scanning and Structure-from-Motion Photogrammetry for steep slope mapping

Both Terrestrial Laser Scanner and Structure from Motion photogrammetry are considered as reliable methods for collecting relief elevation data in the form of dense point clouds. The point density is their common big advantage compared to classical survey measurements. Although both methods produce millions of XYZ points, the manner of collecting data is different resulting in point clouds with serious differences. In the current study these two methodologies for 3D point cloud generation are compared. As a test site is considered a part of a well mapped active landslide in western Greece. In this landslide a terrestrial laser scanner was deployed for the collection of 3D information of the steep slopes. At the same time UAVs flights were performed and dense point clouds were also generated. The derived products from the TLS and UAV are compared and the results are presented.