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Hi Greg, re: what is the source dataset (so I can try to replicate your example) > The source dataset is EAST/CONUS. OK. This should help. re: > Just plot the any image from that > source. The problem is the Mercator projection at 1km resolution from > McIDAS doesn't look like its the right plot area. The Terascan plot covers > the area I would expect from a Mercator plot at 1km resolution. I don't > know how to make the McIDAS plot match the Terascan one. I think that the difference you are seeing is related to the 'slat' positional parameter for the PRO=MERC keyword sequence. You are specifying an 'slat' of '0' (zero, which is the default): imgremap.k $sdset $ddset.$dpos TIME=$time LATLON=$latlon PRO=MERC 0 RES=$res SIZE=$lin $ele SSIZE=ALL BAND=$band If you change 'slat' to 39.25 (the center of the remapped image), the areal coverage is noticeably different: imgremap.k $sdset $ddset.$dpos TIME=$time LATLON=$latlon PRO=MERC 39.25 SIZE=$lin $ele SSIZE=ALL BAND=$band Question: - do you know what Terascan is using for its Mercator parameters? I wouldn't be surprised if the standard latitude used in the Terascan algorithm is the center latitude of the remapped image. Please give the following a try and let me know if the results look more like what you are expecting: $res = 1 $lat = 39.25 $lon = 105.00 $lin = 925 $ele = 1050 $band = 1 imgremap.k $sdset $ddset.$dpos TIME=$time LATLON=$lat $lon PRO=MERC $lat SIZE=$lin $ele SSIZE=ALL BAND=$band Cheers, Tom -- **************************************************************************** Unidata User Support UCAR Unidata Program (303) 497-8642 P.O. Box 3000 address@hidden Boulder, CO 80307 ---------------------------------------------------------------------------- Unidata HomePage http://www.unidata.ucar.edu **************************************************************************** Ticket Details =================== Ticket ID: MMD-610472 Department: Support McIDAS Priority: Normal Status: Closed