ISPRS-Archives The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ISPRS-Archives Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. 2194-9034 Copernicus Publications Göttingen, Germany 10.5194/isprs-archives-XLII-3-W8-157-2019 MULTI-TEMPORAL HIGH-RESOLUTION LANDSLIDE MONITORING BASED ON UAS PHOTOGRAMMETRY AND UAS LIDAR GEOINFORMATION Hung C.-L. J. 1 Tseng C.-W. 1 2 Huang M.-J. https://orcid.org/0000-0002-8416-1121 2 Tseng C.-M. 3 Chang K.-J. 2 Division of Watershed Management, Taiwan Forestry Research Institute, Taipei, Taiwan Dept. of Civil Engineering, National Taipei University of Technology, Taipei, Taiwan Dept. of Land Management and Development, Chang Jung Christian University, Tainan, Taiwan 21 08 2019 XLII-3/W8 157 160 Copyright: © 2019 C.-L. J. Hung et al. 2019 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://isprs-archives.copernicus.org/articles/XLII-3-W8/157/2019/isprs-archives-XLII-3-W8-157-2019.html The full text article is available as a PDF file from https://isprs-archives.copernicus.org/articles/XLII-3-W8/157/2019/isprs-archives-XLII-3-W8-157-2019.pdf

<p>Due to the high seismicity and high annual rainfall, numerous landslides occurred and caused severe impacts in Taiwan. Typhoon Morakot in 2009 brought extreme and long-time rainfall, and caused severe disasters. After 2009, numerous large scale deep-seated landslides may still creeping, however not necessary easily to inspect the activity. In recent years, the remote sensing technology improves rapidly, providing a wide range of image, essential and precious geoinformation. Accordingly, the Small unmanned aircraft system (sUAS) has been widely used in landslide monitoring and geomorphic change detection. This study used UAS to continuously monitor a landslide area in Baolai Village in southern Taiwan, which had a catastrophic landslide event triggered by heavy rainfall caused by Typhoon Morakot in 2009. In order to accesses the potential hazards, this study integrates UAS, field geomatic survey, terrestrial laser scanner (ground LiDAR), and UAS LiDAR for sequential data acquisition since 2015. Based on the methods we are able to construct multi-temporal and high resolution DTMs, so as to access the activity and to monitoring the creeping landslides. The data set are qualified from 21 ground control points (GCPs) and 11 check points (CPs) based on real-time kinematic-global positioning system (RTK-GPS) and VBS RTK-GPS (e-GNSS). More than 10 UAS flight missions for the study areas dated since 2015, for an area large than 5&ndash;40 Km<sup>2</sup> with 8&ndash;12 cm spatial resolution (GSD). Then, the datasets was compared with the airborne LiDAR data, to evaluate the quality and the interpretability of the dataset. Since early 2018, we integrate UAS LiDAR technology to scanning the sliding area. The density of the point cloud data sets are higher than 250 and 100 points/m2 for the total and ground point, respectively. The spatial distributions of geomorphologic changes were quantified firstly with the GCPS and CPs. The potential disaster was evaluated at different times, and the result reveals that most active regions were on the eastern side of the landslide. Significant changes in elevation were detected before the middle of 2017, however reactivated again since middle of 2018. The results of this study provide not only geoinfomatic datasets of hazardous area, but also for essential geomorphologic information/methods for other study, and for hazard mitigation and planning, as well.</p>