Orthorectification of HR satellite images with space-derived DSM

The paper addresses the item of orthorectification of high resolution satellite images and the assessment of the final accuracy achieved when Digital Surface Models (DSM) provided by other remotely sensed data are used. By using a photogrammetric processing, a DSM was obtained from an EROS (Earth Resources Observation System) high resolution stereo pair acquired over a portion of the city of Bologna (Italy). After the accuracy assessment of the terrain model trough the comparison with external Digital Elevation Model (DEM), a broad range of orthorectification procedures with high resolution satellite images (Ikonos, QuickBird and EROS) have been therefore investigated by the authors. The accuracy in final positioning provided by the orthorectification of a QuickBird imagery with the EROS-derived elevation dataset was evaluated using a evenly spaced set of Ground Control Points from GPS survey. The achieved accuracy could meet the requirements needed in technical cartography specifications (to scale as large as 1:10000) updating of well recognizable features or entities and generic mapping procedures.