Add note about GetLegendGraphic and SLD_VERSION

[geographika]

Update the docs to match the implementation in mapwms.cpp.

if (nVersion >= OWS_1_3_0 && sld_version == NULL) {
  msSetErrorWithStatus(MS_WMSERR, MS_HTTP_400_BAD_REQUEST,
                       "Missing required parameter SLD_VERSION",
                       "GetLegendGraphic()");
  return msWMSException(map, nVersion, "MissingParameterValue",
                        wms_exception_format);
}
if (nVersion >= OWS_1_3_0 && strcasecmp(sld_version, "1.1.0") != 0) {
  msSetErrorWithStatus(MS_WMSERR, MS_HTTP_400_BAD_REQUEST,
                       "SLD_VERSION must be 1.1.0", "GetLegendGraphic()");
  return msWMSException(map, nVersion, "InvalidParameterValue",
                        wms_exception_format);
}

[geographika]

Although it does seem strange to have to add that parameter, when it can only ever be one value. GetLegendGraphic doesn't seem to be part of the WMS spec so I'm not sure why it couldn't be added in the code automatically if missing.

[ejn]

Although it does seem strange to have to add that parameter, when it can only ever be one value. GetLegendGraphic doesn't seem to be part of the WMS spec so I'm not sure why it couldn't be added in the code automatically if missing.

GetLegendGraphic is an optional part of the "Styled Layer Descriptor profile of the Web Map Service Implementation Specification" (OGC 05-078r4 seems to be the newest version)

[geographika]

Thanks @ejn. Table 8 — Parameters in GetLegendGraphic operation request in the spec lists it as mandatory:

[jratike80]

It seems that sld_version was introduced in OGC 05-078r4 together with a new SLD version 1.1.0.
The WMS 1.3.0 GetCapabilities contain schema location http://schemas.opengis.net/sld/1.1.0/sld_capabilities.xsd that makes the use of sld_version mandatory.

WMS 1.1.x GetCapabilities contain just <UserDefinedSymbolization SupportSLD="1".
It probably means that with WMS 1.1.x only SDL version 1.0.0 (OGC 02-070) is supported.