Thanks for the replies so far, but I'm obviously missing a trick as it doesnt seem to be working.
The gdalinfo on my TIF looks like this. E:\rasters>gdalinfo tq00ne.tif Driver: GTiff/GeoTIFF Files: tq00ne.tif tq00ne.tfw Size is 7874, 7874 Coordinate System is `' Origin = (505000.000000000000000,110000.000000000000000) Pixel Size = (0.635001270002540,-0.635001270002540) Metadata: TIFFTAG_IMAGEDESCRIPTION=1:10000 TILE TQ00NE TIFFTAG_DATETIME=2008:07:14 23:22:37 TIFFTAG_COPYRIGHT=ORDNANCE SURVEY CROWN COPYRIGHT 2008 TIFFTAG_XRESOLUTION=400 TIFFTAG_YRESOLUTION=400 TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch) Image Structure Metadata: COMPRESSION=LZW INTERLEAVE=BAND Corner Coordinates: Upper Left ( 505000.000, 110000.000) Lower Left ( 505000.000, 105000.000) Upper Right ( 510000.000, 110000.000) Lower Right ( 510000.000, 105000.000) Center ( 507500.000, 107500.000) Band 1 Block=7874x8 Type=Byte, ColorInterp=Palette Image Structure Metadata: NBITS=4 Color Table (RGB with 16 entries) 0: 0,0,0,255 1: 107,107,107,255 2: 90,90,90,255 3: 220,220,220,255 4: 209,209,209,255 5: 243,243,243,255 6: 190,190,190,255 7: 243,243,243,255 8: 190,190,190,255 9: 255,255,255,255 10: 0,0,0,255 11: 0,0,0,255 12: 0,0,0,255 13: 0,0,0,255 14: 0,0,0,255 15: 0,0,0,255 But whenever I try to do a gdalwarp with the using -dstalpha I get an error message and an unsuable TIF file as output E:\rasters>gdalwarp -of GTiff -s_srs "EPSG:27700" -t_srs "EPSG:4326" -co "TFW=YES" -co "TILED=YES" -co "COMPRESS=LZW" -dstalpha TQ00NE.TIF TQwarpa.TIF Copying color table from TQ00NE.TIF to new file. Creating output file that is 9687P x 6132L. ERROR 6: SetColorTable() not supported for multi-sample TIFF files. Processing input file TQ00NE.TIF. 0...10...20...30...40...50...60...70...80...90...100 - done. E:\rasters>gdalwarp -of GTiff -s_srs "EPSG:27700" -t_srs "EPSG:4326" -co "TFW=YES" -co "TILED=YES" -co "COMPRESS=LZW" -dstnodata 12 -dstalpha TQ00NE.TIF TQwarpa.TIF Copying color table from TQ00NE.TIF to new file. Creating output file that is 9687P x 6132L. ERROR 6: SetColorTable() not supported for multi-sample TIFF files. Processing input file TQ00NE.TIF. 0...10...20...30...40...50...60...70...80...90...100 - done. Any more suggestions? Thanks Rob On 18 June 2010 15:06, Chaitanya kumar CH <chaitanya...@gmail.com> wrote: > Rob, > > You can try the -dstalpha option in gdalwarp to create an alpha band. ( > http://www.gdal.org/gdalwarp.html) > > On Fri, Jun 18, 2010 at 7:22 PM, Rob <g...@vanbooth.com> wrote: > >> Hi Guys >> >> I'm reprojecting some rasters from OSGB (EPSG:27700) to WGS84 (EPSG:4326) >> and am running into a problem. >> >> The rasters are reprojecting nicely, but I am left with black pixels >> around the image where the reprojected image doesnt fit squarely within the >> rectangular dimensions of the file. >> >> I posted about this issue a few weeks ago, and then realised that I should >> be marking that colour as transparent when rendering using GeoServer, and >> ho! everything was OK. >> >> However, I am now reprojecting some greyscale rasters, and by making the >> black pixels on the outside transparent, I am losing the black details of >> the raster image that I want to display! >> >> Is there a way of selecting the colour that gdal uses to populate these >> dead pixels around the side? >> >> MTIA >> >> Rob >> >> _______________________________________________ >> gdal-dev mailing list >> gdal-dev@lists.osgeo.org >> http://lists.osgeo.org/mailman/listinfo/gdal-dev >> > > > > -- > Best regards, > Chaitanya kumar CH. > /tʃaɪθənjə/ /kʊmɑr/ > +91-9494447584 > 17.2416N 80.1426E >
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