[gdal-dev] probles by ecw-convert (gdal_translate and expand)

Jan Tappenbeck tappenbeck at widemann.de
Thu Nov 3 06:23:57 EDT 2011

hi !

i had cit-files (microstation) to convert into ecw.

in the first step i transform into tiff by:

gdal_translate -of GTiff  image.cit image.tif

if i get the image-properties by gdalinfo i get following:

C:\Program Files (x86)\FWTools2.4.7>gdalinfo 
Driver: GTiff/GeoTIFF
Files: [pATH]\g8744-1.tif
Size is 16002, 8619
Coordinate System is `'
Origin = (-947485262.477377770000000,-1221704414.522622100000000)
Pixel Size = (3224.954755655543500,-3224.954755655543500)
Image Structure Metadata:
Corner Coordinates:
Upper Left  (-947485262.477,-1221704414.523)
Lower Left  (-947485262.477,-1249500299.562)
Upper Right (-895879536.477,-1221704414.523)
Lower Right (-895879536.477,-1249500299.562)
Center      (-921682399.477,-1235602357.042)
Band 1 Block=16002x1 Type=Byte, ColorInterp=Palette
   Color Table (RGB with 256 entries)
     0: 255,255,255,255
     1: 0,0,0,255
   255: 0,0,0,255

   the image in preview is ok !

   now i convert into ecw by:

   gdal_translate -of ECW image.tif image.ecw

   after start the command i get the information:

   Input file size is 16002, 8619
Warning 6: ECW driver ignores color table. The source raster band will 
be consid
ered as grey level.
Consider using color table expansion (-expand option in gdal_translate)

0...10...20...30...40...50...60...70...80...90...100 - done.

   but now  !  the image is only BLACK !!!!

   can andyone tell me how the command had to be for
   "Consider using color table expansion (-expand option in 
gdal_translate)" ???

   regards Jan :-)

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