Abstract: In the past few years, a new low-cost, efficient photogrammetry mapping method called structure from motion (SfM) was applied to the high-spatial resolution three-dimensional topographic data collection. As the latest and a very significant advance in digital surveying, SfM has only been applied to the geosciences to produce orthophoto mosaics, three-dimensional (3D) point clouds, and digital elevation model (DEM) since 2011. SfM-derived products have been used to detect topographical changes and hence to infer dynamic processes in glacial, fluvial, coastal, hillslope, dryland, volcanic, and shallow underwater environments. In this study, historical imagery archives of 2005 – 2009 acquired from a UAV are processed by using SfM to create hyper-spatial resolution orthophoto mosaics and DEM. A statistical analysis indicates that the results have an overall accuracy of about 0.13 – 0.23m. Precise and detailed data obtained from UAV imagery and SfM photogrammetry are essential for describing fluvial geomorphology and also helpful to detect, monitor and predict fluvial geomorphic processes.
Keywords: fluvial remote sensing; UAV; SfM; orthophoto mosaics; DEM