ACCURACY EVALUATION OF DEM EXTRACTED FROM HIGH RESOLUTION SATELLITE STEREOPAIRS OF FLAT AREAS SUBJECTED TO RIVER FLOODS

With regard to the monitoring of the hydraulic hazard, a very important role is played by studies concerning the outflow of water after river floods or downpours. Such studies are based on complex forecasting hydraulic models, which need an accurate DSM with all the natural and anthropic objects which may interfere with the outflow of water. The aim of this work is the evaluation of DSMs extracted from high resolution stereo pairs acquired over the area of Ferrara. The best workflow to generate the DSM has been evaluated: the orientation has been performed both with the commercial software PCI Geomatica v10.2 and with the scientific software SISAR, developed by La Sapienza University of Rome. Image matching and DEM extraction have been performed with PCI Geomatica and SISAR matching facility but also, for the image matching, with the scientific software DPCOR, developed by Leibniz University of Hannover. The DSM accuracy has been evaluated comparing a reference DSM derived from a photogrammetric flight with all the extracted DSMs.