GENERATION AND VALIDATION OF HIGH-RESOLUTION DEMS FROM WORLDVIEW-2 STEREO DATA

Abstract

WorldView-2 (WV-2), whose panchromatic images have a 05m ground sampling distance (GSD), was launched by DigitalGlobe in 2009. It is the first commercial satellite to offer 8-band multispectral imagery with 18m resolution. Due to the off-nadir sensor rotation of WV-2, it is feasible to obtain stereo coverage. Digital elevation models (DEMs) have been created with three WV-2 stereopairs of northern Istanbul with different land types and one of these is comprehensively analysed in this study. A reference DEM, developed from large-scale aerial photogrammetric mapping, together with a lidar DEM and an overlapping neighbouring WV-2 DEM, are used for validation. The generated WV-2 DEM reached, after filtering and in open areas, a standard deviation in height of approximately 10 GSD. A higher number of discrepancies larger than 4m exist than would be expected from a normal distribution, influencing the standard deviation more than the normalised median absolute deviation (NMAD).