It sounds like the GCP file that you restore has the x and y coordinates for the GCPs stored in UTM coordinates.  Is that right?  I wonder how you generated this GCP file?  And then, are you saying that when you restore these in the GCP Selection dialog in ENVI,  they look right in the list of GCPs (i.e., the UTM easting and northing coordinates are shown)?  But then if you click on one of the GCPs in the list, ENVI interprets the easting and northing as lat/long?  Does it take you to the GCP in the display?  Are the GCPs displayed correctly when you restore them?  Then if you go ahead with the orthorectification, you get a blank image? I see what you mean about it not saving more than 2 decimal places.  That does seem problematic.  But I'm told that it's only problematic if the output projection (and thus the GCP coordinates) are Geographic lat/long.  That's not a valid projection for an orthorectification.  So, I guess what you are supposed to do is set your projection to UTM, and then enter your GCPs in UTM coordinates, and do the orthorectification that way.  But what you seem to be saying is that that is not possible.  ENVI automatically interprets the UTM coordinates as lat/long, right? If I'm right about what's happening, then I recommend you send this issue in to ITT VIS tech support (support@ittvis.com), and send your data (at least the GCPs that you are restoring).  There may be a bug that needs to be logged, or maybe there's just some extra step that we can recommend to you after playing with your data. Peg