[gdal-dev] 8-bit GeoTIFF and transparency over multiple bands

[Vincent Schut]

D wrote:
> I would need to know, if a three band (RGB) 8-bit GeoTIFF can have 
> transparency enabled?

No, there would be no way to know the transparency for a pixel if there 
are only red/green/blue values available. For that you'll need a 4-band 
(rgba) image.
>  
> I know that it is possible to enable transparency on a singleband TIFF.

In that case you'd have one band containing color indices instead of rgb 
color values. These color indices than map into a rgba colortable which 
defines color and transparency for that color index.
>  
> Can someone confirm this?
>  
> Best regards,
> Dejan Gregor
> 
> 
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