[mapserver-users] Two questions about WMS and outputformats

[Rahkonen Jukka]

Frank Warmerdam wrote:

> Aihe: Re: [mapserver-users] Two questions about WMS and outputformats
> 
> Rahkonen Jukka wrote:
> > Hi,
> > 
> > By default, without having any OUTPUTFORMAT sections in the 
> mapfile, 
> > Mapserver is advertising following imageformats in WMS 
> GetCapabilities
> > document:
> > 
> >  <GetMap>
> >       <Format>image/gif</Format>
> >       <Format>image/png</Format>
> >       <Format>image/png; mode=24bit</Format>
> >       <Format>image/jpeg</Format>
> >       <Format>image/vnd.wap.wbmp</Format>
> >       <Format>image/tiff</Format>
> >       <Format>image/svg+xml</Format>
> > 
> > Some users have been confused because WMS client builds menu items 
> > according to that list, but at least "image/png; mode 24bit" and 
> > "image/tiff" do not give any output. What is the reason to include 
> > these formats in getCapabilities by default, if they do not work 
> > without creating OUTPUTFORMATs in the mapfile first?
> 
> Jukka,
> 
> I don't know why image/tiff and image/png; mode=24bit would not work.
> Perhaps you could file a ticket with minimal details to 
> reproduce this problem.  Please include the mapserv -v string 
> in the ticket so I can try to reproduce a similar scenario.  
> Assign the ticket directly to me.

I repeated the test in a more controlled way.  Image/tiff works, but
image/png; mode=24bit does not work.  The other advertised format that
does not work is image/svg xml.

> > Second question is about JPEG outputformat. It works 
> through GD with 
> > these settings  OUTPUTFORMAT
> >       NAME "jpeg"
> >       MIMETYPE "image/jpeg"
> >       DRIVER "GD/JPEG"
> >       EXTENSION "jpg"
> >       IMAGEMODE RGB
> >  END
> > 
> > If I change driver to "GDAL/JPEG" I get this error on ms 
> errorlog [Mon 
> > Mar 16 11:16:05 2009].825000 msSaveImageGDAL(): General 
> error message. 
> > Failed to create output JPEG file.
> > JPEG driver doesn't support 4 bands.  Must be 1 (grey) or 3 
> (RGB) bands.
> > 
> > What makes GDAL/JPEG driver to believe that I want 4 bands? 
> Or is it 
> > just best to use DG/JPEG always?
> 
> I'm surprised.  This should not occur with IMAGEMODE RGB.  I 
> would appreciate your also filing a ticket on this issue and 
> assigning it to me.

It does occur with the Mapserver versions I was testing (5.2.0, 5.2.1
and 5.3-dev). I am filing two tickets.

-Jukka-