module documentation
WMS provider.
References.
- OGC 01-068r3: WMS 1.1.1
- OGC 06-042: WMS 1.3.0
see also https://docs.geoserver.org/latest/en/user/services/wms/reference.html
A note on layer order:
Internally we always list source layers topmost layer first, which corresponds to the layer tree display.
WMS capabilities are assumed to be top-first by default, for servers with bottom-first caps, set bottomFirst=True, in which case the capabilities parser will revert all layer lists.
The order of GetMap is always bottom first:
> A WMS shall render the requested layers by drawing the leftmost in the list bottommost, > the next one over that, and so on. (OGC 06-042, 7.3.3.3)
therefore when invoking GetMap, our layer lists should be reversed.