Urban correction for the hydrological conditioning of the TanDEM-X DEM for the HydroSHEDS v2 database

Abstract

The HydroSHEDS database provides global hydrographic data for hydrological applications. The second, refined version of the database is improved by using the highresolution TanDEM-X digital elevation model (DEM). In order to derive hydrologic data from the terrain, during the socalled pre-conditioning, the DEM is edited and ancillary layers are calculated. Prior steps of the editing include, among others like void and outlier correction and the derivation of a coastline and water body mask, an urban correction. When river networks are derived from a DEM, visible artificial structures can divert the streams as they intercept the natural course of the riverbed. Therefore, during the last step of the pre-conditioning, the urban correction aims to reduce such diversions caused by built-up structures.