Web Map Service

An Open Geospatial Consortium Web Map Service (WMS) produces maps of spatially referenced data dynamically from geographic information. This international standard defines a "map" to be a portrayal of geographic information as a digital image file suitable for display on a computer screen. A map is not the data itself. WMS-produced maps are generally rendered in a pictorial format such as PNG, GIF or JPEG, or occasionally as vector-based graphical elements in Scalable Vector Graphics (SVG) or Web Computer Graphics Metafile (WebCGM) formats. This is in contrast to a Web Feature Service (WFS), which returns actual vector data, and a Web Coverage Service (WCS), which returns actual raster data.

This International Standard defines three operations:
# returns service-level metadata
# returns a map with well-defined geographic and dimensional parameters
# returns information about particular features shown on a map (optional)

Web Map Service operations can be invoked using a standard web browser by submitting requests in the form of Uniform Resource Locators (URLs). The content of such URLs depends on which operation is requested. In particular, when requesting a map the URL indicates what information is to be shown on the map, what portion of the earth is to be mapped, the desired coordinate reference system, and the output image width and height. When two or more maps are produced with the same geographic parameters and output size, the results can be accurately overlaid to produce a composite map. The use of image formats that support transparent backgrounds (e.g., GIF or PNG) allows underlying maps to be visible. Furthermore, individual maps can be requested from different servers. The Web Map Service thus enables the creation of a network of distributed map servers from which clients canbuild customized maps.

A Web Map Service is usually not invoked directly. More often, it is invoked by a client application that provides the user with interactive controls. This client application may or may not be web-based.

Some WMS Clients

These mapping tools can act as WMS clients:
*ArcGIS Desktop
*ArcGIS Explorer
*ArcGIS .NET and Java ADF
*Google Earth
*gvSIG
*NASA World Wind
*OpenLayers
*Ossimplanet
*uDig
*Qgis
* [http://dapple.geosoft.com/ Dapple]
*IDV_Solutions Visual Fusion Experience

Some WMS Servers

*ArcGIS Server
*ArcIMS
*GeoServer
*Mapserver
*Mapnik
*Oracle MapViewer
*MapGuide Open Source
*SuperMap IS.Net
*SuperMap IS Java
*SuperMap iServer
*CARIS Spatial Fusion Enterprise
*GeoMedia
*IDV_Solutions Visual Fusion Server

External links

* [http://portal.opengeospatial.org/files/?artifact_id=14416 OpenGIS® Web Map Service (WMS) Implementation Specification, Version 1.3.0, 2006-Mar-15, 06-042]
* [http://wms-sites.com Visual catalog of WMS resources]
* [http://www.skylab-mobilesystems.com/en/wms_serverlist.html List of OGC WMS Services]
* [http://freshmeat.net/projects/spot/ Spot (GPS and WMS-Client for mobile devices)]
* [http://ExploreOurPla.net/gis/maps/ Search and view public WMS server and layer]
* [http://www.ogc-services.net/ OGC-Services.NET - Free List of OGC Services] (New Services can be added manually)
* [http://www.easywms.com/ SUAS Mapserver (open source extended WMS-Server)]
* [http://www.geoconnections.org/en/communities/developers/standards/fa=technical.web_map_service GeoConnections WMS description]