Per-request styling of map features

It is possible to ask GeoServer to render features in a style that does not exist within its own catalog. This ability to do per-request styling is also referred to as external styles.

Note

Per-request styling of map features is part of the OGC WMS standard. Any web mapping software that conforms to the standard will contain a similar capability. As this is a book on GeoServer, we will explore GeoServer's implementation of the WMS standard.

There are three different ways in which an external style can be provided to GeoServer:

• The SLD= parameter can be set on the GetMap GET request to point at an Internet-accessible SLD file

• The SLD_BODY= parameter can be set on the GetMap GET request to provide the SLD document as a URL-encoded XML

• The SLD can be provided in the XML GetMap POST request body

The mode in which GeoServer works to apply the styling depends on whether or not the LAYERS parameter is included in the GetMap request. When the LAYERS parameter is not...