Analysis of ASTER Multispectral Stereo Imagery to Update DEM and Land Cover Databases for Cyprus Island

This study presents the production of Digital Elevation Models (DEM) and land cover (LC) databases for the islands of Cyprus, capable of being used in local studies. The 1:50.000 topographic maps present a nominal horizontal accuracy of 20 m and a nominal vertical accuracy of 10 m with 90% confidence. The Advanced Spaceborn Thermal Emission and Reflection Radiometer (ASTER) offer along-track stereoscopic viewing capability. Its viewing geometry is suitable for DEM generation even without the use of ground control points. Recent studies have proved that in this case the vertical accuracy of DEM can be better than 20 m. In this paper we therefore examine the production of DEM and LC maps using ASTER multispectral stereo-imagery for the island of Cyprus. These products are capable of updating the 1:50.000 topographic maps of the island, as well as capable of supporting water resources management. A DEM from digitized contours from the 1:50.000 topographic maps was created and compared with ASTER derived DEMs. Several survey monuments were used to estimate the accuracy of these DEMs. It was founded that the horizontal and vertical accuracy of the ASTER derived DEM is similar to the respective accuracies of the DEM derived from digitized contours, therefore optical comparison of these two DEMs and statistical analysis can immediately prove if there is any need for update to the topographic maps. The CORINE 2000 LC map was used to evaluate the ASTER derived LC for Cyprus. The classification accuracy was better than 75%, therefore the ASTER derived LC map can be used to detect and update recent LC changes.