[gdal-dev] gtiff with internal mask

[Duarte Carreira]

I'm trying to create gtiffs with transparent areas where there are voids between my original images.

I have successfully done it by using an alpha band but this process created 3x larger images. I think partly because of an additional 4th band and partly because I cannot use ycbcr to compress with jpeg. So I thought of using internal masks expecting to get smaller images but cannot get it to work.

When converting from the rgba image using -mask 4 I cannot "see" the transparency and get black areas:

gdal_translate -b 1 -b 2 -b 3 -ma sk 4 --config GDAL_TIFF_INTERNAL_MASK YES test_alpha.tif test_internalmask.tif

I tried looking at the images using qgis and paint.net.

Any hints or help appreciated.

Thanks,
Duarte














Duarte Carreira
Diretor | Dep. Informa??o Geogr?fica e Cartografia

www.edia.pt<http://www.edia.pt>
www.alqueva.com.pt<http://www.alqueva.com.pt>
Tel. +351 284315100

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