[mapserver-users] 16 Bit PNG Output

[Frank Warmerdam]

On 11-04-07 08:19 AM, kaipi wrote:
> I am not able to output elevation data as 16 Bit PNGs. Is Mapserver not able
> to to this ?
> I tried with a current version of Mapserver on Windows and on Linux. I tried
> WMS and WCS requests - but I always get 8 Bit PNGs back although I have
> configured 16INT. Other formats like GTiff or Esri Bil work fine with 16Int.
>
> Any ideas ?
>
> Thanks,
>
> kaipi
>
> Here is my mapfile:
>
>    [...]
>
>    OUTPUTFORMAT
>     NAME 'tif'
>     DRIVER GDAL/GTIFF
>     IMAGEMODE INT16
>     MIMETYPE "image/tif"
>    END
>
>    OUTPUTFORMAT
>     NAME 'pngint16'
>     DRIVER GDAL/PNG
>     IMAGEMODE INT16
>     MIMETYPE "image/pngint16"
>    END

Harry,

I suspect the problem is that the PNG driver supposed unsigned 16bit
integer while IMAGEMODE INT16 is signed 16bit integers.  We really need
a FORMATOPTION that will let us force the pixel data type of the generated
file even if it is somewhat different from the IMAGEMODE type.  Perhaps you
could create an enhancement ticket for this and ensure it is assigned to me
(userid: warmerdam)?

It should be a pretty easy change.

Best regards,
-- 
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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    | Geospatial Programmer for Rent