On Mon, Dec 15, 2008 at 4:24 PM, Gosselin, Andre <[email protected]> wrote: > Hi, > > I have a LAYER based on a gtiff file reported as follows by gdalinfo : > > Band 1 Block=10800x1 Type=Byte, ColorInterp=Palette > NoData Value=255 > Color Table (RGB with 256 entries) > 0: 255,0,255,255 > 1: 250,0,255,255 > 2: 240,0,255,255 > 3: 230,0,255,255 > (snip) > 253: 143,0,0,255 > 254: 140,0,0,255 > 255: 0,0,0,255 > > I would like Mapserver to produce a gtiff output with the same palette as > the above one, eg with > 255 as the nodata value. I just cannot see how to do that. Whatever I try, > it appears that the missing value is always assigned to palette index 0 in > the > output tiff file. For ex. here is what gdalinfo reports for the output file > : > > Band 1 Block=1000x8 Type=Byte, ColorInterp=Palette > Color Table (RGB with 256 entries) > 0: 0,0,0,255 > 1: 255,0,255,255 > 2: 250,0,255,255 > 3: 240,0,255,255 > (snip) > 252: 150,0,0,255 > 253: 147,0,0,255 > 254: 143,0,0,255 > 255: 140,0,0,255 > > Note that there is no explicit "NoData Value= " indication. The input color > palette has been "shifted down" by one position, with the former > "255:0,0,0,255" entry now at top as "0: 0,0,0,255". > > This annoying, because the byte values in the output tiff file do not match > anymore those in the input file. > > Is there away to avoid this problem (except requiring all my source tiff > layers to be rewritten to use 0 as the nodata value instead of 255, which > would be a big pain given their high number). > > Regards, > > Andre Gosselin > Maurice Lamontagne Institute
Hi Andre: How did you get Mapserver to produce a paletted Gtiff output image? Are you making a WMS GetMap request? I am trying to preserve the palette in a WCS GetCoverage request without success (I get a grayscale image), and I am interested in your solution. Also, how have you configured the output format in your .map file? Thanks in advance, Alex _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users
