[gdal-dev] Force output color interpretation

[Even Rouault]

Asger

it appears that when translating to GeoTIFF and that the photometric 
interpretation creation option is not set, the GeoTIFF driver will try to 
make a best guess and write the interpretation as RGBA.

You can achieve what you want by specifying the photometric interpretation 
creation option with :

gdal_translate 2km.tif out.tif -co PHOTOMETRIC=RGB

Best regards,
Even

Le Thursday 11 December 2008 12:01:26 Asger Sigurd Skovbo Petersen, vous avez 
écrit :
> Hi all,
>
>
>
> I'm having problems with the color interpretation of the output from
> GDAL utilities. I have some 4 band (Red, Green, Blue, Near infrared)
> rasters. The fourth band is interpreted as "Undefined" by GDAL, but GDAL
> insists on marking the fourth band as ALPHA in the output. Having the
> fourth band marked as ALPHA causes a bunch of problems with other
> software, so I would really like the GDAL tools to leave it as
> "Undefined". Is this possible?
>
>
>
> Please find a simple example below where gdal_translate marks fourth
> band as ALPHA.
>
>
>
> Best regards
>
> Asger
>
>
>
> Example:
>
> c:\>gdalinfo --version
>
> GDAL 1.6.0dev, FWTools 2.2.6, released 2008/08/22
>
> c:\>gdalinfo 2km.tif
>
> Warning 1: TIFFFetchNormalTag:Incompatible type for "RichTIFFIPTC"; tag
> ignored
>
> Driver: GTiff/GeoTIFF
>
> Files: 2km.tif
>
> Size is 10000, 10000
>
> Coordinate System is `'
>
> Origin = (580000.000000000000000,6330000.000000000000000)
>
> Pixel Size = (0.200000000000000,-0.200000000000000)
>
> Metadata:
>
>   TIFFTAG_SOFTWARE=Adobe Photoshop CS4 Windows
>
>   TIFFTAG_DATETIME=2008:12:09 17:27:10
>
>   TIFFTAG_XRESOLUTION=72
>
>   TIFFTAG_YRESOLUTION=72
>
>   TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
>
> Image Structure Metadata:
>
>   INTERLEAVE=PIXEL
>
> Corner Coordinates:
>
> Upper Left  (  580000.000, 6330000.000)
>
> Lower Left  (  580000.000, 6328000.000)
>
> Upper Right (  582000.000, 6330000.000)
>
> Lower Right (  582000.000, 6328000.000)
>
> Center      (  581000.000, 6329000.000)
>
> Band 1 Block=10000x1 Type=Byte, ColorInterp=Red
>
> Band 2 Block=10000x1 Type=Byte, ColorInterp=Green
>
> Band 3 Block=10000x1 Type=Byte, ColorInterp=Blue
>
> Band 4 Block=10000x1 Type=Byte, ColorInterp=Undefined
>
>
>
> c:\>gdal_translate 2km.tif out.tif
>
> Warning 1: TIFFFetchNormalTag:Incompatible type for "RichTIFFIPTC"; tag
> ignored
>
> Input file size is 10000, 10000
>
> 0...10...20...30...40...50...60...70...80...90...100 - done.
>
>
>
> c:\>gdalinfo out.tif
>
> Driver: GTiff/GeoTIFF
>
> Files: out.tif
>
> Size is 10000, 10000
>
> Coordinate System is `'
>
> Origin = (580000.000000000000000,6330000.000000000000000)
>
> Pixel Size = (0.200000000000000,-0.200000000000000)
>
> Metadata:
>
>   TIFFTAG_SOFTWARE=Adobe Photoshop CS4 Windows
>
>   TIFFTAG_DATETIME=2008:12:09 17:27:10
>
>   TIFFTAG_XRESOLUTION=72
>
>   TIFFTAG_YRESOLUTION=72
>
>   TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
>
> Image Structure Metadata:
>
>   INTERLEAVE=PIXEL
>
> Corner Coordinates:
>
> Upper Left  (  580000.000, 6330000.000)
>
> Lower Left  (  580000.000, 6328000.000)
>
> Upper Right (  582000.000, 6330000.000)
>
> Lower Right (  582000.000, 6328000.000)
>
> Center      (  581000.000, 6329000.000)
>
> Band 1 Block=10000x1 Type=Byte, ColorInterp=Red
>
>   Mask Flags: PER_DATASET ALPHA
>
> Band 2 Block=10000x1 Type=Byte, ColorInterp=Green
>
>   Mask Flags: PER_DATASET ALPHA
>
> Band 3 Block=10000x1 Type=Byte, ColorInterp=Blue
>
>   Mask Flags: PER_DATASET ALPHA
>
> Band 4 Block=10000x1 Type=Byte, ColorInterp=Alpha