[gdal-dev] GeoTiff and the 4th band

[Nicolas Mayer]

Hello

I have a problem with the geotiff (GTiff) driver.

I create a 4-bands raster image in a c++ program. The fourth band was
considered as an alpha band in the geotiff image (actually, it is near
infrared : NIR)

$ gdalinfo new_geotiff.tif
Driver: GTiff/GeoTIFF
Files: new__geotiff.tif
Size is 100, 100
(...)
Band 1 Block=100x20 Type=Byte, ColorInterp=Red
  Mask Flags: PER_DATASET ALPHA
Band 2 Block=100x20 Type=Byte, ColorInterp=Green
  Mask Flags: PER_DATASET ALPHA
Band 3 Block=100x20 Type=Byte, ColorInterp=Blue
  Mask Flags: PER_DATASET ALPHA
Band 4 Block=100x20 Type=Byte, ColorInterp=Alpha

How to remove the Color interpretation 'alpha' and the mask flags ?

I want to have :

Band 1 Block=100x20 Type=Byte, ColorInterp=Red
Band 2 Block=100x20 Type=Byte, ColorInterp=Green
Band 3 Block=100x20 Type=Byte, ColorInterp=Blue
Band 4 Block=100x20 Type=Byte, ColorInterp=Undefined

I already tryed :
pDS->GetRasterBand(4)->SetColorInterpretation(GCI_Undefined );

I tryed too to set the creation option : "ALPHA" to "NO".


Thanks in advance for any help.

Nicky
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