There are two different codes that can be used to specify the GRS 80 datum in a .tab file. Although they seem to me they should be equivalent, they are clearly not because adjacent raster images using the different codes are shifted relative to each other. Here is the info [paraphrased] from the Users Guide: Number Datum Area Ellipsoid 33 [GRS 80] Worldwide GRS 80 74 [NAD 83] [N and Cntl America] GRS 80 Are these specifications actually equivalent or not? If not, why not? If so, why do adjacent images shift? Drew "perpetually pursuing precision" Phillips ________________________ Andrew Phillips, Ph.D. Quaternary Geology Section Illinois State Geological Survey ________________________ ---------------------------------------------------------------------- To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]