Comparison of UAV-based LiDAR and Photogrammetry Case Study: Litchfield SuperSite, Australia

Abstract

In the last decade Light Detection and Ranging (LiDAR) and structure-for-motion (SfM) photogrammetry became the two leading techniques for gathering 3D point cloud data. Especially combined with an Unmanned Aerial Vehicle (UAV) these two techniques have shown to be useful for environmental studies or forestry. The low costs for UAV-based SfM photogrammetry is one of the main advantages of this technique. LiDAR on the other hand has the advantage that it allows to map the ground even with vegetation cover. This research aims to determine to which point structure-for-motion photogrammetry can be used as a replacement to LiDAR in savanna ecosystems. This is done in the first step by comparing Digital Terrain Model (DTM), Digital Surface Model (DSM), and Canopy Height Model (CHM). In the second step forest parameters, as tree count, Diameter at Breast Height (DBH), canopy area in m², gap area in m², are being compared. It was found that the photogrammetric derived digital models can be used as an alternative to the LiDAR derived models and further it can be used as an alternative for estimating most of the forest parameters. The DBH could not be calculated for a single tree in either of the two datasets, when the results of the tree segmentation are used.