[gdal-dev] Creating jpeg compressed tiff with alpha

Even Rouault even.rouault at mines-paris.org
Mon Jul 2 03:56:45 PDT 2012


Your command worked fine. It is just that your expectations are wrong. It will
produce a mask band, and not a alpha band. This is indicated by the following
line in the gdalinfo report :

>   Mask Flags: PER_DATASET

(a mask band that is common to all the regular bands of the dataset)

Mask bands can be obtained with GDALGetMaskBand(). But admitedly, I guess that
few software packages are able to deal with them. For example, recent versions
of MapServer will try using mask band if no alpha band is found.

Best regards,


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