[Gdal-dev] Conversion of paletted PNG to ECW does not work

[Brent Fraser]

Frank,

   I don't think ECW supports palettes.  As a work-around we
can convert the files to 24-bit then ECW, so no big problem.

    My thought was the same as the original poster's: either
have GDAL do the 8-bit to 24-bit conversion as part of the
format translation (for convenience and to save on temporary
disk space), or at least produce a warning message that
paletted files are not supported (this would save time on
user support!)

Thanks!
Brent Fraser
GeoAnalytic Inc.
Calgary, Alberta

----- Original Message ----- 
From: "Frank Warmerdam" <warmerdam at pobox.com>
To: "Brent Fraser" <bfraser at geoanalytic.com>
Cc: <gdal-dev at lists.maptools.org>
Sent: Tuesday, July 03, 2007 1:54 PM
Subject: Re: [Gdal-dev] Conversion of paletted PNG to ECW
does not work


> Brent Fraser wrote:
> > Frank,
> >
> >   Do you know if a bug was ever filed for this? (I have
the
> > same problem with paletted tiffs)
>
> brent,
>
> I'm afraid this is a "feature" not a bug.  As far as I
know ECW
> does not support palettes, so you are expected to convert
to RGB
> before writing to ECW, using a tool like pct2rgb.py.
>
> If you believe ECW is supposed to support palettes then
please file
> a bug with details.
>
> Best regards,
> -- 
> ---------------------------------------+------------------
--------------------
> I set the clouds in motion - turn up   | Frank Warmerdam,
warmerdam at pobox.com
> light and sound - activate the windows |
http://pobox.com/~warmerdam
> and watch the world go round - Rush    | President OSGeo,
http://osgeo.org
>