A WMS (Web Map Service) request that retrieves data, for a pixel location on a map.

A GetFeatureInfo request retrieves data that the WMS service provider wishes to provide for a pixel location on a map.

Support for the GetFeatureInfo is optional per layer in a WMS. Support for a GetFeatureInfo request is indicated by the queryable attribute in a WMS GetCapabilities response, that is:

<!--- Below layer does not support GetFeatureInfo requests --->
<Layer queryable="0" opaque="0" cascaded="0">

<!--- Below layer supports GetFeatureInfo requests --->
<Layer queryable="1" opaque="0" cascaded="0">

A service will normally support several output formats for the request, such output formats are advertised in the GetCapabilities response, for example: