DELINEATING COASTAL EROSION AND LANDSLIDE USING GNSS, LIDAR, AND UAV-BORNE PHOTOGRAMMETRY INTEGRATED METHODS

Date

2020-08

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Abstract

Terrestrial Laser Scanning (TLS), Airborne Laser Scanning (ALS) and Unmanned Aerial Vehicle (UAV) photogrammetry are state-of-the-art geodetic imaging techniques. This dissertation has developed integrated methods for conducting high-accuracy geological hazards monitoring using GNSS, ground-based and airborne Light Detection and Ranging (LiDAR), and UAV-photogrammetry integrated techniques. A rapid data processing method for deriving high-accuracy and high-resolution Digital Elevation Models (DEMs) from dense point clouds is introduced. In the method, the spatial aliasing problem occurred during regridding dense point clouds is solved by applying a fourth-order Butterworth low-pass spatial filter. The cutoff wavelength for the filter is recommended to be three times the grid size of the target DEM. To reduce surveying time and simplify field operational tasks, a rapid TLS surveying method that requires only one reflector in the field has been developed. The rapid TLS surveys can achieve an elevation accuracy (RMS) of approximately 3-5 cm for georeferenced points and 2-3 cm for DEMs. A method for obtaining control points from LiDAR point clouds for UAV photogrammetric surveys is also introduced. This method allows rapid, high-accuracy, and low-cost high-accuracy UAV photogrammetry survey for geological hazards studies. The integrated methods have been applied for coastal erosion studies at Freeport, Texas and landslide monitoring at the Slumgullion landslide in Hinsdale County, Colorado. According to this study, beach and foredune areas adjacent to the Brazoria River in Freeport, Texas lost massive sands during the three-year period before and after Hurricane Harvey (2015-2018), no significant recovery was observed in the summer of 2018; while the beach and dune area 2 km away from the river mouth remained stable or even slightly gained sands during the three years. The middle portion of the Slumgullion landslide moves at a speed of 1.4 cm/day towards the downhill direction during the summer season.

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Keywords

LiDAR, UAV, Digital Elevation Model, Shoreline, Landslide

Citation

Portions of this document appear in: Xiong, L., Wang, G., Wessel, P., 2017. Anti-aliasing filters for deriving high-accuracy DEMs from TLS data: A case study from Freeport, Texas. Computers & Geosciences, 100, 125-134; and in: Xiong, L., Wang, G., Bao, Y., Zhou, X., Wang, K., Liu, H., Sun, X., Zhao, R., 2019. A Rapid Terrestrial Laser Scanning Method for Coastal Erosion Studies: A Case Study at Freeport, Texas, USA. Sensors, 19(15), 3252.