[mapserver-users] JPEG and OVERSAMPLE_RATIO

[Cédric MOULLET]

I realize that links have been sent and not pictures
Here are reachable links for the three cases:
1.
https://picasaweb.google.com/lh/photo/j_OClw5fGOeQE7K1wiimytMTjNZETYmyPJy0liipFm0?feat=directlink
2.
https://picasaweb.google.com/lh/photo/3q52h52EwOp9JzZm3KAWbNMTjNZETYmyPJy0liipFm0?feat=directlink
3.
https://picasaweb.google.com/lh/photo/GTAThw7AOVMK-j-7DWAabtMTjNZETYmyPJy0liipFm0?feat=directlink
Cédric


On Mon, Dec 17, 2012 at 4:11 PM, Cédric MOULLET <cedric.moullet at gmail.com>wrote:

> Hi,
> The following issue has been observed with MapServer 6.0.3:
>
> 1. Very good quality for a PNG with RESAMPLE=BILINEAR and
> OVERSAMPLE_RATIO=16:
> [image:
> http://wms-bgdi.bgdi.admin.ch/?lang=xx&LAYERS=ch.swisstopo.pixelkarte-grau-pk100_bazl&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A21781&BBOX=513184,143152,519840,149808&WIDTH=256&HEIGHT=256]
>
> 2. Less good quality for a PNG or JPEG with default resampling settings:
> [image:
> http://wms-bgdi.bgdi.admin.ch/?lang=xx&LAYERS=ch.swisstopo.pixelkarte-grau-pk100_original&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A21781&BBOX=513184,143152,519840,149808&WIDTH=256&HEIGHT=256]
>
> 3. Awful quality for JPEG with RESAMPLE=BILINEAR and OVERSAMPLE_RATIO=16:
> [image:
> http://wms-bgdi.bgdi.admin.ch/?lang=xx&LAYERS=ch.swisstopo.pixelkarte-grau-pk100_bazl&FORMAT=image%2Fjpeg&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A21781&BBOX=513184,143152,519840,149808&WIDTH=256&HEIGHT=256]
>
> Any idea why the OVERSAMPLE_RATIO affects heavily the quality of JPEG
> images ?
>
> Thanks in advance for your help,
> Cédric
>



-- 
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Home sweet home:
http://map.geo.admin.ch/?crosshair=bowl&zoom=11&X=185241.24219&Y=561288.90625&bgOpacity=0&selectedNode=node_ch.swisstopo.fixpunkte-lage1
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