Building Topological Flow-path Networks based on scale-adaptive DEM

In this study, we propose to simulate the dynamics of surface flow using a Topological Flow-path Network model (TFN) based on scale-adaptive DEMs (S-DEMs). This model makes full use of the high accuracy DEM data to extract topographical and hydrological characteristics from the terrain surface. It also assigns these characteristics with scale properties, thus building a stream-network-bounded scale-adaptive DEM system. For each DEM, a triangulated irregular network (TIN) surface is established and flow direction is calculated for each triangular facet in the TIN, building the flow paths from any location in the DEM to the basin outlet, such that a three-dimensional terrain expression is simplified to a one dimension topology flow structure. For each flow path, hydrological variables, such as flow velocity and volume, are computed using classic hydrological formula to support cross-scale simulation of the surface water dynamics.