Working with WMS
From Wildsong
Find out what a WMS service can do
Start with the basic URL, this is the OGC reference server. This will just return a (relatively useless) informational message.
http://metaspatial.net/cgi-bin/ogc-wms.xml
Then add the GetCapabilities request (note these are not supposed to be case sensitive, so REQUEST=request)
http://metaspatial.net/cgi-bin/ogc-wms.xml?request=GetCapabilities&service=wms
This will return an extensive XML file with the capabilities of the server listed.
Find out about a layer
Plucking the name of a layer from the GetCapabilities request, I can ask for more information. If I omit the version I get an error.
http://metaspatial.net/cgi-bin/ogc-wms.xml?service=wms&request=DescribeLayer&layer=OGC-WMS_reference-server_with_Ordnance_Survey_OpenData&version=1.3.0
Setting the SRS
In my case, the default for this server is to return its images in the spatial referece setting "EPSG=4326" which is unprojected WGS84. What I need is Oregon state system which is "EPSG=2992"
I can add the SRS like this:
http://wms.oregonexplorer.info/ImageX/ecw_wms.dll?SRS=EPSG:2992