Good morning! I'm going to show you my work with the MODIS Images. By making a co-register on a basic image , i'll obtain many mistakes about very high RMS and given that the major mistakes are in the CGP located in the sea. I'd like to make a Sea Mask to be superimposed on every image whitch has been noticedat different moments to solve this problem. Then i'll co-register them. Images are about the mediterran sea, could you help me to make a sea mask? are there appropriate functions in envi? Has somebosy done experiences about this? Colud you suggest me some other ways to reduce RMS or delete GCP in the sea? Thank for your help.