Hi, I have to do some works like this:  generate ROIs from one image, and then use these ROIs to another dataset. the image and the dataset have the different map projections, samples and lines. Since routineslike  ENVI_GET_ROI_IDS and ENVI_GET_ROI_DATA need to use FID and NS,NL or POS as parameters, these routines do not works in this situation. So, any one can tell me how to achieve this in IDL? Thanks.