[OpenLayers-Dev] WMS should default to GIF instead of JPG

[Cameron Shorter]

Chris suggested I raise the issue on this list. I've taking the liberty 
of tracking it as well:

http://trac.openlayers.org/ticket/423#preview


Currently, the image format that a WMS defaults to is JPG. JPG is best 
used to display photos and the like which contains millions of colors. 
It compresses well, however it is lossy and doesn't allow transparency. 
It is a good format for a aerial photo basemaps.

For WMS layers, which are usually placed over a photo basemap like 
GoogleMaps?, GIF is a better format. GIF is lossless and works best for 
images with a fixed number of colors (as is usually returned by WMS 
layers). GIF allows transparency.

And for the record, PNG has similar properties to GIF, but older 
versions of IE have problems rendering PNG layers, so is not a suggested 
format.

So I suggest that the default format offered by the Openlayers WMS is 
GIF format instead of JPG as is currently the case.
-- 
Cameron Shorter
http://cameron.shorter.net