JPL operates a WMS server (described at http://onearth.jpl.nasa.gov/tiled.html) that has a number of worldwide elevation and imagery datasets. In order to keep their server load down, however, they operate a non-standard WMS server; their service does not support the requesting of arbitrary bounding boxes. Instead, requests must match tile boundaries, which are reported by a special "GetTileService" request. Would it be possible to add support for this type of service as a source?
There was a previous mailing-list discussion on this topic at: