katrin eggert wrote: > Hello Markus > Thank you for your answer. Just a few more questions :) > >> >> There is no preprocessing required before orthorectification, apart >> from the organisation of the imagery. The imagery to be orthorectified >> should be in a xy location. A separate location with the target CRS >> must exist and should hold reference imagery if you do not have Ground >> Control Points. >> > 1- My VHR image has already coordinates. Is this a problem?
No. Sorry for the confusion, usually the imagery to be georectified comes without any CRS and thus goes into a xy coordinate system. If the imagery already has a CRS, you can use that, and source and target location can be identical. To avoid confusion, mapsets should be different. > 2- Shall I apply Geometric Correction procedure before Orthorectification? No, it would introduce more errors. Markus M _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user