Jan, Your original image has a color table with RGBA values. Since it includes the alpha channel, you can just modify the color table to set the entry for 0 to (0,0,0,0). With a 0 value for alpha, the pixels with 0 value will be transparent.
But you can set it using the VRT format. This method has been discussed in this list earlier[1]. However, you have to reapply the whole table's entries. It might be easier to change the color table using a desktop GIS application. [1]: http://lists.osgeo.org/pipermail/gdal-dev/2011-May/028854.html On Mon, Nov 28, 2011 at 4:40 PM, Jan Tappenbeck <[email protected]>wrote: > > > HI ! > > after my problems to transform rasterimage now i have a problem to make > the white background tranparency. > > After the translation the new image had following status: > > C:\Program Files (x86)\FWTools2.4.7>gdalinfo "D:\City\raster\gas\500\twf_* > *chec > k\baseline_etrs.tif" > Driver: GTiff/GeoTIFF > Files: D:\City\raster\gas\500\twf_**check\baseline_etrs.tif > Size is 16568, 9564 > Coordinate System is: > PROJCS["ETRS89 / UTM zone 32N", > GEOGCS["ETRS89", > DATUM["European_Terrestrial_**Reference_System_1989", > SPHEROID["GRS 1980",6378137,298.**2572221010002, > AUTHORITY["EPSG","7019"]], > AUTHORITY["EPSG","6258"]], > PRIMEM["Greenwich",0], > UNIT["degree",0.**0174532925199433], > AUTHORITY["EPSG","4258"]], > PROJECTION["Transverse_**Mercator"], > PARAMETER["latitude_of_origin"**,0], > PARAMETER["central_meridian",**9], > PARAMETER["scale_factor",0.**9996], > PARAMETER["false_easting",**500000], > PARAMETER["false_northing",0], > UNIT["metre",1, > AUTHORITY["EPSG","9001"]], > AUTHORITY["EPSG","25832"]] > Origin = (380297.397497169380000,**5745229.623735004100000) > Pixel Size = (0.032091644585721,-0.**032091644585721) > Metadata: > AREA_OR_POINT=Area > Image Structure Metadata: > INTERLEAVE=BAND > Corner Coordinates: > Upper Left ( 380297.397, 5745229.624) ( 7d15'44.21"E, 51d50'42.10"N) > Lower Left ( 380297.397, 5744922.699) ( 7d15'44.59"E, 51d50'32.17"N) > Upper Right ( 380829.092, 5745229.624) ( 7d16'11.98"E, 51d50'42.51"N) > Lower Right ( 380829.092, 5744922.699) ( 7d16'12.36"E, 51d50'32.58"N) > Center ( 380563.245, 5745076.161) ( 7d15'58.29"E, 51d50'37.34"N) > Band 1 Block=16568x1 Type=Byte, ColorInterp=Palette > Color Table (RGB with 256 entries) > 0: 255,255,255,255 > 1: 0,0,0,255 > 2: 0,0,0,255 > 3: 0,0,0,255 > 4: 0,0,0,255 > 5: 0,0,0,255 > 6: 0,0,0,255 > 7: 0,0,0,255 > 8: 0,0,0,255 > 9: 0,0,0,255 > 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 > .... > > i try to make the image transparency by > > C:\Program Files (x86)\FWTools2.4.7>gdalwarp -srcnodata 0 -dstalpha > "D:\City\ > raster\gas\500\twf_check\**baseline_etrs.tif" "D:\City\raster\gas\500\twf_ > **check > \baseline_etrs_t.tif" > Copying color table from D:\City\raster\gas\500\twf_**check\baseline_etrs.tif > t > o new file. > Creating output file that is 16568P x 9564L. > ERROR 6: SetColorTable() not supported for multi-sample TIFF files. > Processing input file D:\City\raster\gas\500\twf_** > check\baseline_etrs.tif. > > but there comes the message "ERROR 6: SetColorTable() not supported for > multi-sample TIFF files." and the result image is only 1 Color !!!!!!!! > > the status now is > C:\Program Files (x86)\FWTools2.4.7>gdalinfo "D:\City\raster\gas\500\twf_* > *chec > k\baseline_etrs_t.tif" > Driver: GTiff/GeoTIFF > Files: D:\City\raster\gas\500\twf_**check\baseline_etrs_t.tif > Size is 16568, 9564 > Coordinate System is: > PROJCS["ETRS89 / UTM zone 32N", > GEOGCS["ETRS89", > DATUM["European_Terrestrial_**Reference_System_1989", > SPHEROID["GRS 1980",6378137,298.**2572221010002, > AUTHORITY["EPSG","7019"]], > AUTHORITY["EPSG","6258"]], > PRIMEM["Greenwich",0], > UNIT["degree",0.**0174532925199433], > AUTHORITY["EPSG","4258"]], > PROJECTION["Transverse_**Mercator"], > PARAMETER["latitude_of_origin"**,0], > PARAMETER["central_meridian",**9], > PARAMETER["scale_factor",0.**9996], > PARAMETER["false_easting",**500000], > PARAMETER["false_northing",0], > UNIT["metre",1, > AUTHORITY["EPSG","9001"]], > AUTHORITY["EPSG","25832"]] > Origin = (380297.397497169380000,**5745229.623735004100000) > Pixel Size = (0.032091644585733,-0.**032091644585733) > Metadata: > AREA_OR_POINT=Area > Image Structure Metadata: > INTERLEAVE=PIXEL > Corner Coordinates: > Upper Left ( 380297.397, 5745229.624) ( 7d15'44.21"E, 51d50'42.10"N) > Lower Left ( 380297.397, 5744922.699) ( 7d15'44.59"E, 51d50'32.17"N) > Upper Right ( 380829.092, 5745229.624) ( 7d16'11.98"E, 51d50'42.51"N) > Lower Right ( 380829.092, 5744922.699) ( 7d16'12.36"E, 51d50'32.58"N) > Center ( 380563.245, 5745076.161) ( 7d15'58.29"E, 51d50'37.34"N) > Band 1 Block=16568x1 Type=Byte, ColorInterp=Gray > Mask Flags: PER_DATASET ALPHA > Band 2 Block=16568x1 Type=Byte, ColorInterp=Alpha > > Can anyone help me ?? > > reagards Jan :-) > > > > > ______________________________**_________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/**mailman/listinfo/gdal-dev<http://lists.osgeo.org/mailman/listinfo/gdal-dev> > -- Best regards, Chaitanya kumar CH. +91-9494447584 17.2416N 80.1426E
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