[mapserver-users] OUTPUTFORMAT png 16-bits

[Jeff McKenna]

Hi Johannes,

I just wanted to mention that what I always test OUTPUTFORMAT with is 
through the shp2img commandline utility, with the "-i" switch, such as:

   shp2img -m test.map -o ttt.png -i PNG16 -all_debug 5

PS. in the future MapServer v8.0 I hope to help change that utility name 
to "map2img", so it makes more sense.


-jeff



-- 
Jeff McKenna
MapServer Consulting and Training Services
https://gatewaygeomatics.com/




On 2020-02-05 6:02 a.m., Johannes Paul wrote:
> 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
> 
>