serviceWMS

SERVICE=WMS is a query parameter used in the Web Map Service (WMS) protocol defined by the Open Geospatial Consortium (OGC). It identifies the type of service that a client is invoking in a request and is a core element of the protocol’s key-value pair (KVP) encoding.

In standard WMS requests, the service parameter must indicate the WMS service. It is typically sent together with the REQUEST parameter, which specifies the operation to perform (for example, GetCapabilities or GetMap). The service value helps servers distinguish WMS requests from other OGC services such as WFS or WCS, enabling appropriate processing and response.

Common usage examples include:

- GetCapabilities: service=WMS&request=GetCapabilities&version=1.3.0

- GetMap: service=WMS&request=GetMap&layers=example&styles=&crs=EPSG:4326&bbox=-180,-90,180,90&width=800&height=600&format=image/png

The service parameter is defined in the WMS specifications and is expected to be present in KVP-encoded requests. Servers typically require service=WMS to respond correctly; omitting or misnaming the parameter can lead to errors or unexpected results.

Relation to capabilities and operations: the GetCapabilities request uses the service parameter to advertise the available maps, formats, and version support. The presence and value of service help ensure that clients and servers interpret requests consistently, supporting interoperability across different implementations.

Limitations and considerations: while the canonical value is "WMS" (often case-sensitive in strict implementations), some servers may be lenient with case. As with other critical request parameters, proper encoding and adherence to the respective WMS version are essential for reliable operation.