Tidal Creek Extraction from Airborne LiDAR Data Using Ground Filtering Techniques

As elongated indentations or valleys in a wetland caused by tidal currents, tidal creeks act as drainage pathways and promote tidal flat evolution. Determining their geometric information is essential for topographical research of tidal flats. The airborne light detection and ranging (LiDAR) system has been the most efficient surveying technique in tidal topography because it can directly acquire precise geo-referenced point clouds for wide areas. Existing tidal creek extraction methods using airborne LiDAR data have limitations such as excessive user intervention, lack of adaptability to various shapes and sizes of tidal creeks, and decreased precision due to conversion to the digital elevation model. This study aims to overcome these limitations and effectively extract various types of tidal creeks by utilizing ground filtering which is a technique to filter off-ground objects (such as buildings, trees, etc.) in land LiDAR surveys. To derive a suitable method for tidal creek extraction, three verified ground filtering techniques, adaptive triangulated irregular network, gLiDAR, and cloth simulation filtering (CSF), were selected and tested using LiDAR point data. We modified the application procedure and optimized their parameters to enable tidal creek extraction. Our results confirmed that CSF can extract various tidal creeks with minimal user intervention. Finally, we calculated their depths and generated a tidal creek map.