A Web Map Service (WMS) is a standard protocol for serving georeferenced map images over the Internet
WMS is a widely supported format for maps and GIS data accessed via the Internet and loaded into client side GIS software.
It also specifies a number of different request types, two of which are required by any WMS server:
- GetCapabilities - returns parameters about the WMS and the available layers
- GetMap - with parameters provided, returns a map image
Optionally (within the strict standard), WMS may also support
- GetFeatureInfo - with parameters provided, returns attributes from the data at a point location.
WMS may offer any number of vendor specific operations which will be declared within the GetCapabilities response, an example of a vendor specific operation is:
- GetStyles (MapServer)
Commonly, WMS servers have some Styled Layer Descriptor (SLD) capability, such SLD enabled WMS may support the following operations:
- DescribeLayer
- GetLegendGraphic
OpenGIS® Web Map Server Implementation Specification
Styled Layer Descriptor profile of the Web Map Service Implementation Specification
