DTMs generation from satellite stereo images: Accuracy tests in mountain region

Digital Terrain Models (DTM) represent an effective tool for many applications and in particular for terrain morphology investigation and orthoimages generation. The availability of satellite stereo images allows to generate updated DTMs through digital photogrammetric algorithms especially in those areas where old and poor maps exist. In this work we show some quality tests results about DEMs obtained from ASTER data (15m geometric resolution), elaborated through commercial software. We consider this information very important to understand which kind of applications can reasonably use these data. Shown results refer to a mountain area located in the NW Italian Alps, characterized by different height type regions (flat, hilly, mountain) whose evaluation can drive to consistent results for a better understanding of limits and forces of these data. Such tests, making use of the commercial software AsterDTM, take into consideration both qualitative and quantitative aspects. Height profiles comparisons, statistical analysis on differences and data mining have been carried out in order to evaluate accuracies and to define the nature of possible systematic errors. Reference data is the available Regional DTM (50m x 50m grid, accuracy of 2.5m) and the single height points extracted from technical maps at 1: 10000 scale for more precise local investigation.