A Web Map Service (WMS) is a standard protocol developed by the Open Geospatial Consortium in 1999 for serving georeferenced map images over the Internet. These images are typically produced by a map server from data provided by a GIS database. History The Open Geospatial Consortium (OGC) became involved in developing standards for web mapping after a paper was published in 1997 by Allan Doyle, outlining a "WWW Mapping Framework". The OGC established a task force to come up with a strategy, and organized the "Web Mapping Testbed" initiative, inviting pilot web mapping projects that built upon ideas by Doyle and the OGC task force. Results of the pilot projects were demonstrated in September 1999, and a second phase of pilot projects ended in April 2000. The Open Geospatial Consortium released WMS version 1.0.0 in April 2000, followed by version 1.1.0 in June 2001, and version 1.1.1 in January 2002. The OGC released WMS version 1.3.0 in January 2004. Requests WMS specifies a number of different request types, two of which are required by any WMS server: GetCapabilities – returns parameters about the WMS (such as map image format and WMS version compatibility) and the available layers (map bounding box, coordinate reference systems, URI of the data and whether the layer is mostly opaque or not) GetMap – returns a map image. Parameters include: width and height of the map, coordinate reference system, rendering style, image format Request types that WMS providers may optionally support include: GetFeatureInfo – if a layer is marked as 'queryable' then you can request data about a coordinate of the map image. DescribeLayer – returns the feature types of the specified layer or layers, which can be further described using WFS or WCS requests. This request is dependent on the Styled Layer Descriptor (SLD) Profile of WMS. GetLegendGraphic – return an image of the map's legend image, giving a visual guide to map elements. All communication is served through HTTP. Map image A WMS server usually serves the map in a bitmap format, e.g. PNG, GIF, JPEG, etc. In addition, vector graphics can be included, such as points, lines, curves and text, expressed in SVG or WebCGM format. Software Open source software that provide web map services capability include: deegree GeoServer MapServer MapGuide Open Source QGIS Server Proprietary server software that allow providing web map services include: ArcGIS Server ArcIMS Cubeserv from Terrapixel GeoWebPublisher from