terrain-hydrology

Always invoke for terrain, drainage, viewshed, or visibility analysis from elevation, even before the DEM or correct surface is chosen. Covers DTM-versus-DSM selection, slope, aspect, curvature, hillshade, conditioning, flow direction/accumulation, streams, watersheds, and catchments. Use point-cloud-lidar first only when an elevation surface must be created from LiDAR or photogrammetric points.