Bare Earth LiDAR to Gridded Topography for the Pascagoula River, MS: An Accuracy Assessment

This paper investigates the development of an optimal bare-earth LiDAR-derived digital elevation model for use in a shallow water equations model for a portion of the Pascagoula River Basin (coastal Mississippi). It is vital to represent the floodplain topography as accurately as possible, since terrain is the first factor that can promote or inhibit water flow. An essential step is processing the dense LiDAR points to a DEM or FEM; however, it is crucial that the correct interpolation scheme and grid size is employed for an efficient and accurate terrain representation. In the presented research, several DEMs and FEMs were developed and three interpolation routines were tested. Three paths for interpolation were considered and elevation error was computed for each: 1) LiDAR to DEM; 2) LiDAR to FEM; and 3) LiDAR to DEM to FEM. The error of each interpolation scheme is assessed in terms of root mean square error, and a relationship between DEM grid size and finite element mesh size was found. This paper aims to determine the most appropriate and efficient interpolation routine and grid size for this region for use in a two-dimensional shallow water equations model.