I use gdalwarp with python to overlay polygons on ENVISAT radar images. Everything goes well for this type of images but when I try with SENTINEL images, gdal does not find the georeferencing. It seems that gdal takes the global coordinates of the pixel at the upper left of the image. When I read the image information with gdalinfo, I realize that ENVISAT images have no gcp while SENTINEL images have. I have this error message when I use gdalwarp with SENTINEL images:
The transformation is already "north up" or a transformation between pixel/line and georeferenced coordinates cannot be computed for tmp_spill.tif. There is no affine transformation and no GCPs. Specify transformation option SRC_METHOD=NO_GEOTRANSFORM to bypassthis check.
I do not understand why it does not find gcps when they display well with gdalinfo. I use this line for overlay polygon on ENVISAT images :
cmd='gdalwarp --config GDALWARP_IGNORE_BAD_CUTLINE YES -q -dstnodata None -cutline tmp.shp %s %s'%('tmp_seep.tif',classout_seep).
Do you know why gdal does not find gcps coordinates ?