Web Mapping Illustrated

Name

Web Feature Service (WFS)

Synopsis

WFS is an Open Geospatial Consortium specification. For more information about the format itself, see http://www.opengeospatial.org/.

WFS allows a client to retrieve geospatial data encoded in Geography Markup Language (GML) from multiple Web Feature Services. GML is built on the standard web language XML.

WFS differs from the popular Web Map Service specification in that WFS returns a subset of the data in valid GML format, not just a graphic image of data.

Capabilities

Requesting capabilities using the GetCapabilities request to a WFS server returns an XML document showing what layers and projections are available, etc.

Example of a WFS GetCapabilities URL

    http://www2.dmsolutions.ca/cgi-bin/mswfs_gmap
    ?VERSION=1.0.0
    &SERVICE=wfs
    &REQUEST=GetCapabilities

Example of the resulting XML from GetCapabilties

Example B-1. Resulting XML from GetCapabilities

... <FeatureTypeList> <Operations> <Query/> </Operations> <FeatureType> <Name>park</Name> <Title>Parks</Title> <SRS>EPSG:42304</SRS> <LatLongBoundingBox minx="-173.433" miny="41.4271" maxx="-13.0481" maxy="83.7466" /> </FeatureType> <FeatureType> <Name>road</Name> <Title>Roads</Title> <SRS>EPSG:42304</SRS> <LatLongBoundingBox minx="-148.059" miny="35.882" maxx="-33.7745" maxy="72.5503" /> </FeatureType> <FeatureType> <Name>popplace</Name> <Title>Cities</Title> <SRS>EPSG:42304</SRS> <LatLongBoundingBox minx="-172.301" miny="36.3541" maxx="-12.9698" maxy="83.4832" /> </FeatureType> </FeatureTypeList> ... ...