[mapserver-users] JPG is bad rendered in some computers ?

[Rahkonen Jukka]

Hi,

Forget the WMS clients for a while and send WMS requests from your browser so you can have more control on what really happens.

This should return quite a sharp jpeg image:
http://oriondata.homedns.org:8542/cgi-bin/mapserv_jpeg?REQUEST=GetMap&SERVICE=WMS&VERSION=1.1.1&WIDTH=663&HEIGHT=536&LAYERS=mascara&TRANSPARENT=TRUE&FORMAT=image%2Fjpeg&BBOX=477741.3106567791,5339772.595359228,479456.0484341582,5341158.869037471&SRS=EPSG:32719&STYLES=

This one not so beautiful 8-bit png:
http://oriondata.homedns.org:8542/cgi-bin/mapserv_jpeg?REQUEST=GetMap&SERVICE=WMS&VERSION=1.1.1&WIDTH=663&HEIGHT=536&LAYERS=mascara&TRANSPARENT=TRUE&FORMAT=image%2Fpng&BBOX=477741.3106567791,5339772.595359228,479456.0484341582,5341158.869037471&SRS=EPSG:32719&STYLES=

And finally this a top-quality but large 24-bit png:
http://oriondata.homedns.org:8542/cgi-bin/mapserv_jpeg?REQUEST=GetMap&SERVICE=WMS&VERSION=1.1.1&WIDTH=663&HEIGHT=536&LAYERS=mascara&TRANSPARENT=TRUE&FORMAT=image%2Fpng%3B+mode%3D24bit&BBOX=477741.3106567791,5339772.595359228,479456.0484341582,5341158.869037471&SRS=EPSG:32719&STYLES=

I believe this is somehow related to your WMS clients and not to hardware.  I tried your service with OpenJUMP and Windows Vista and for me all the formats I tried (jpeg, gif, 8-bit png and 24-bit png) are OK. Less colours in 8-bit formats is a fact and not an issue.

I see you have set image extension to "jpeg". I cannot see anything wrong with that but have a try with "jpg" anyway.

-Jukka Rahkonen-


Vincent Blanqué wrote:
 
Hi,

It appears that you are right, the client only allows loading PNG
format. I tested with Arcgis and QGis in the 'bad' computer only PNG
format is available, BUT in the 'good', PNG, JPEG, PNG and TIFF are
available for the same WMS url:
http://oriondata.homedns.org:8542/cgi-bin/mapserv_jpeg?

Do you have any explanation to this strange behaviour ?

In the 'bad' computer, the grafical card is: NVDIA GForce 7050 PV/630A
in the 'good' one: ATI Radeon HD 2600... The issue could be relative to
the kind of graphical card ?

Thx,

Vincent



Rahkonen Jukka a écrit :
> Hi,
> 
> I strongly believe that Mapserver is sending identical jpegs to all your computers and the reason is somewhere in the WMS client side. That does not mean that everything is OK and you should just suffer.
> 
> Investigate the jpeg files that Mapserver is sending by saving some samples on disk.  Open saved images with image processing software and have a look at image information. Are images technically identical on each computer?  If they are then there must be some differencies in your WMS clients or their settings.
> 
> My guess is that the bad jpeg is not a jpeg at all but your WMS client is asking for 8-bit png or gif.
> 
> -Jukka Rahkonen-
> 
> Vincent Blanqué wrote:
> 
> 
>> Hi,
>>
>> I have a problem with a WMS service in JPEG format. With 
>> various computers, I have a bad rendering of the JPEG tiles 
>> while with another rendering is perfect. You can watch 
>> screenshots joint to understand better the issue.
>>
>> My mapfile is written like:
>>
>> IMAGEQUALITY 95
>> IMAGETYPE jpeg
>>
>> OUTPUTFORMAT
>> 	NAME jpeg
>> 	DRIVER 'GD/JPEG'
>> 	MIMETYPE 'image/jpeg'
>> 	IMAGEMODE RGB
>> 	EXTENSION 'jpeg'
>> END
>>
>> If you have any solution ?
>>
>> Thanks,
>>
>> Vincent
>>
>>
>>
>