High resolution interferometric SAR DEMs for hydrological network derivation

An experiment was carried out over the Thames basin in the UK to derive a 1" (20 m) Digital Elevation Model (DEM) from ERS tandem IfSAR using a commercially available processing system from Phoenix Systems. A quality assessment is shown of the IfSAR-DEM when compared against DTED-1 (100 m resolution, courtesy of MCE Feltham, UK) and the Institute of Hydrology's hydrological DTM (IHDTM), a 50 m DTM derived from water features and contours from Ordnance Survey 1:50,000 maps. Hydrological network extraction algorithms were applied to the IfSAR-DEM and the subsequent networks were compared against those available from cartographic sources. An assessment is made of the potential value of such IfSAR-DEMs for global high resolution hydrological network extraction, particularly in the light of the forthcoming NASA SRTM mission.