[Gdal-dev] gdal_merge.py and 24 bit images with black border

[Vojtech Honzik]

Would you give me a hint how to utilize fourth (alpha) band to make RGB 24 
bit mosaic? The only hint I got was to use switch -n for no data. 
Unfortunately there is no way how to set a triplet RGB as a parameter. As 
being novice to Python as well as GDAL API, I would like to ask you for hint 
how to make transparent cells with the values 0 0 0 (black) from input.
I have found a script rgbmask.py that adds fourth channel with the values 0 
and 255, but I don't know how to handle with this channel.
Thank you for your hints.

Vojtech Honzik
tel.: +420 777 136 711
e-mail: v.honzik at gmail.com

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