Web Map Service
An OGC standard protocol for serving georeferenced map images over the internet, allowing GIS applications to display layers from remote servers.
Detailed Definition
A Web Map Service (WMS) is a standard protocol defined by the Open Geospatial Consortium (OGC) for serving georeferenced map images over the internet. WMS allows client applications to request and display map layers from remote servers without downloading the underlying data.
How WMS works: - The client sends an HTTP request specifying the map extent, layers, and image format - The server renders the requested map layers into an image - The server returns the image to the client for display - The image is georeferenced (aligned to the correct geographic position)
- GetCapabilities: Returns metadata about available layers and supported parameters
- GetMap: Returns a map image for specified layers, extent, and format
- GetFeatureInfo: Returns attribute information for a point clicked on the map (optional)
Advantages: - No data download required (server-side rendering) - Always displays the latest data from the server - Multiple layers can be combined from different servers - Widely supported by GIS software and web mapping applications - Standardized protocol ensures interoperability
Limitations: - Returns images, not data (cannot query or analyze without separate data download) - Performance depends on server capacity and network speed - Image quality limited by server rendering capabilities - Cannot style or symbolize data on the client side (server controls appearance)
Mining and land management applications: - BLM land status and mining claims layers - USGS geological map services - State agency regulatory map services - Satellite imagery base maps - Environmental and ecological data layers
WMS services are commonly used to add reference layers from authoritative sources to GIS projects without maintaining local copies of the data.
Related Terms
GIS
Geographic Information System - software and technology for capturing, storing, analyzing, and displaying geographically referenced data.
Spatial Data
Data that describes the location, shape, and relationship of geographic features, including vector and raster formats.
Tile Service
A method of serving pre-rendered map images in small tiles at multiple zoom levels for fast web map display.
Web Feature Service
An OGC standard protocol for serving vector geographic features over the internet, allowing clients to query and download spatial data.