Basin division method for TIN-based DEM with Face-Node-Edge flow mode

Abstract

The basin serving as a basic unit is of great importance for flood inundation and other hydrological fields. Most existing basin division methods have been proposed for a raster-based DEM and used in some hydrological software, such as the ArcHydro tool and the RiverTool. Unfortunately, raster has some limitations when compared to TIN; specifically, it cannot depict real ground water flow accurately and reasonably. Referring to the natural law of gravity, which dictates water flowing from high to low areas, we present a Face-Node-Edge (FNE) flow mode for TIN-based DEM. The FNE flow mode assumes the water on each triangle facet flows to its lowest node initially. The water on the lowest node then flows along the steepest edge to its neighbour node; the flow continues until the neighbour nodes' elevations are higher than its own. Meanwhile, upstream triangles pass their flow flags to the downstream triangles along the flow path. After that we can generate basins according to the flags. The case studies demonstrate that the proposed FNE flow mode and basin division method for TIN-based DEM are correct, which can provide more reasonable basin division results than raster, e.g., the ArcHydro tool.