[mapserver-users] OUTPUTFORMAT png 16-bits

Wed Feb 5 02:09:56 PST 2020

Hi,

I would make a test by using some other mimetype, like image/png16, for eliminating the possibility that some internal  png configuration drives over your own outputformat.

I don’t know if it helps but it is cheap to test.

-Jukka Rahkonen-

Lähettäjä: mapserver-users <mapserver-users-bounces at lists.osgeo.org> Puolesta Johannes Paul
Lähetetty: keskiviikko 5. helmikuuta 2020 12.03
Vastaanottaja: mapserver-users at lists.osgeo.org
Aihe: [mapserver-users] OUTPUTFORMAT png 16-bits

Hello,
I'm using Mapserver to output PNG 16-bits DEM raster from .HGT elevation data.
I'm using the below output format definition :

OUTPUTFORMAT

  NAME PNG16

  DRIVER GDAL/PNG

  MIMETYPE image/png

  IMAGEMODE INT16

  EXTENSION "png"

END
However I keep on getting the standard PNG 8-bits out of mapserver.

The strange thing being that when I use a similar config to get GeoTiff 16-bits, I do get what I'm asking for :

OUTPUTFORMAT
  NAME GEOTIFF16
  DRIVER GDAL/GTiff
  MIMETYPE image/tiff
  IMAGEMODE INT16
  EXTENSION "tiff"
END

Could that be an issue with the GDAL/PNG driver ? It seems that the GDAL/PNG driver supports only CreateCopy() and not Create(), where the GDAL/GTiff driver supports both ... Could that be it ? I suspect the GDAL/PNG driver so I also sent my issue to the GDAL mailing list.

I can see from the mailing list that other users already had a similar issue, but there is no obvious reason or solution provided.
https://lists.osgeo.org/pipermail/mapserver-users/2011-April/068428.html
https://lists.osgeo.org/pipermail/mapserver-users/2012-January/071310.html

For information, I'm using GDAL v2.1.3 and Mapserver v7.0.1
Thanks,
Johannes

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