Open Geospatial Consortium (OGC) Web Mapping Services (WMS)

The Open Geospatial Consortium (OGC) has defined Web Mapping Service (WMS) specification protocols for the transfer of geospatial data from servers to client applications. A Web Map Service (WMS) produces an image (e.g. GIF, JPG) of geospatial data.

WMS gives clients access to an image of data without storing a local copy of the dataset. Using a specially structured http request, you can call a dataset (eg. orthoimagery, highways) into your GIS software application.

Receiving an image of the data works well for imagery and other raster data, but means that standard GIS analysis is not feasible using WMS. Web Feature Services (WFS) protocols, on the other hand, do support actual data feature transfer, but very few services currently exist.

WMS Standards

Connection Instructions

To connect to a WMS, select and copy a WMS link and paste the link where your software asks to specify a WMS URL.

Screenshot of Add WMS Server GUI

If using ArcGIS:

  • Click "Add Data" and in the "Look In" window, scroll down near the bottom to "GIS Servers"
  • Choose "Add WMS Server" or one of the other options if you know the host server is running one of those platforms.
  • In the window that opens (pictured at right), copy/paste the WMS URL link and click "Get Layers" to initiate a connection. Once the Server Layers window is populated, click OK.

More extensive help documentation is available with your software.


WMS Indexes and Servers

  • USGS Data - US List
    Links for numerous services, including: Orthoimagery (High Resolution, NAIP), Elevation (NED), Land Cover
  • - Global Catalog
    "Find and Monitor Public Map Services" Services appear to be added by crawlers that add to the site index.
  • - Global Catalog
    ESRI's clearinghouse for map services. Services get added to this index from user contributions.
  • - US Catalog
    Data originates primarily from government and academic sources. Click Advanced Search Options, and then check the box for "Live Data and Maps" specify "WMS" as the keyword. In the search results, go into the details of any WMS service entry and find the WMS URL under "Service Availability"
  • Skylab Mobilesystems - Global List
    Very large lists of links - use Search tools.