Akademik Veri Yönetim Sistemi
20th ISPRS Congress on Technical Commission I 2004, İstanbul, Türkiye, 12 - 23 Temmuz 2004, cilt.35, ss.184-188
© 2004 International Society for Photogrammetry and Remote Sensing. All rights reserved.The high and very high resolution space images are often not available as original or near to original data but as geo-referenced rectified images. The geo-reference is based on the satellite position together with the known attitudes. In the case of IKONOS as lowest level product the CARTERRA Geo, a projection of the original image to a plane with constant height is distributed. For QuickBird the Basic Imagery which is just improved by the internal geometry, is available only as a full scene; less expensive sub-scenes are distributed as Standard Imagery rectified to the rough digital elevation model GTOPO30 or as Ortho Ready Standard Imagery rectified to a plane with constant height like CARTERRA Geo. Also SPOT images are sold as corresponding level 1B-product like also IRS-1C/1D, ASTER and KVR-1000 data. With additional cost for some products the relation between such rectified images and the ground coordinate system is available as rational polynomial coefficients (RPC). The direct geo-reference for the RPCs is not accurate enough and has to be improved at least by a shift to control points. Other solutions are approximations and don't use the direct sensor orientation like the 3D-affine transformation. In some orientation programs the original images are reconstructed based on the rectified images like described by SPOT Image. For the precise geo-referencing the datum shift or higher degree transformation in addition to the terrain depending improvement based on the height differences of the individual points against the reference plane has to be determined. This requires the knowledge of the imaging ray from the actual projection centre to the point in the rectified and geo-referenced image. The view direction from the scene centres to the satellite orbit is available in all cases. Based on this, together with the general known satellite orbit, the individual view directions can be reconstructed without additional information. This strict solution requires the smallest number of control points like also the RPCs, but without additional financial effort. In the area of Zonguldak, Turkey several very high and high resolution space images are available as rectified and geo-referenced products. The precise geo-referencing of these scenes has been made by GPS control points by means of the described method, reconstructing the direction of the imaging rays and requiring only a minimal number of control points.