[gdal-dev] Cannot set transparent color for GeoTIFFs

[Ralf Wagner]

Thanks a lot!!!
It was crucial - to expand color table to RGB! After that everything 
works perfect.
Once again: big thank you!

Ralf Wagner

Chaitanya kumar CH pisze:
> From what Ed said, editing the color table is useless. Try to expand 
> the tiff to rgb and proceed from there. At least the error message 
> should change. ;-)
>
> On Mon, Feb 8, 2010 at 8:52 PM, Grissom, Edward (Ed) 
> <ed.grissom at intergraph.com <mailto:ed.grissom at intergraph.com>> wrote:
>
>
>     Are you aware that the TIFF (and GeoTIFF) spec does not allow you
>     to set
>     a transparent color ?
>
>     The TIFF spec allows a transparency bit-mask or an alpha channel
>     -- each
>     of which covers the entire image, but does not allow a specific color
>     value to be used as transparent.
>
>     I believe that the spec also forbids a alpha channel on the color
>     table
>     itself.   It may allow one on a color indexed image, but it may be
>     that
>     GDAL has not implemented support for that yet.
>
>
>
>     --
>     ed grissom
>     ed.grissom at intergraph.com <mailto:ed.grissom at intergraph.com>
>
>
>
>
> -- 
> Best regards,
> Chaitanya kumar CH.
> /tʃaɪθənjə/ /kʊmɑr/
> +91-9848167848
> 17.241582N 80.142635E


-- 
Ralf Wagner



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