A WMS request uses a HTTP GET request to retrieve information from an internet map server. Common WMS Get requests include GetMap, GetCapabilities, and GetFeatureInfo.

• GetMap
  Retrieves a map consisting of one or more layers from a WMS site


• GetCapabilities
  Provides service metadata in an XML document


• GetFeatureInfo
  Prodives information about a feature on a map based on pixel location

Each request will consist of a series of parameters specifying the map server. service, the WMS version, the request type, output format, and rendering options.

The following are required parameters for most WMS requests.

• Service
  Which service types at a particular server are being invoked


• Version
  Request version. Valid values are 1.0.0, 1.1.0, 1.1.1, and 1.3.0


• Request
  Request name. Valid values include GetMap, GetCapabilities, and GetFeatureInfo

Additionally, each Get request will contain a series of required and optional parameters. These parameters vary by request as well as version. For specifics, see the Web Map Service (WMS) Implementation Specification and each of the GET examples below.

The following URL requests a transparent map with two layers in png format from the OGI map server:

http://ogi.state.ok.us/geoserver/wms?VERSION=1.1.1&REQUEST=GetMap&SERVICE=WMS&LAYERS=ogi:okcounties,ogi:okcities&SRS=EPSG:4326&BBOX=-104.5005,32.7501,-94.01,37.20&WIDTH=800&HEIGHT=300&FORMAT=image/png&STYLES=&TRANSPARENT=TRUE

The resulting image of this request:

The the table below lists the parameters used in the above request:

The following URL requests an XML document containing OGI map server capabilities.

http://ogi.state.ok.us/geoserver/wms?VERSION=1.1.1&REQUEST=GetCapabilities&SERVICE=WMS&

The parameters used in the above request are described in the below table:

To retrieve attribute information of a particular WMS layer, use a URL similar to the following.

http://ogi.state.ok.us/geoserver/wms?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetFeatureInfo&SRS=EPSG:4326&BBOX=-104.5005,32.7501,-94.01,37.20&WIDTH=800&HEIGHT=300&LAYERS=ogi:okcounties&QUERY_LAYERS=ogi:okcounties&STYLES=&X=550&Y=105&

The above request queries the Oklahoma Counties (ogi:okcounties) layer at a specified location, resulting in the following response:

The GetFeatureInfo includes most of the original GetMap request parameters plus several additional parameters.

ArcGIS Desktop is a suite of desktop GIS applications designed for geospatial data management, viewing, editing, and analysis.

Note: Different versions of ArcGIS handle WMS requests differently, though the connection steps are virtually identicial. The following instructions are for ArcGIS 9.3.

To add a WMS layer to ArcGIS, you must first establish a connection with a map server. This can be done with ArcCatalog or directly within ArcMap.

In ArcCatalog: Expand the GIS Servers folder in the catalog tree Double click Add WMS Server In the URL text box, enter http://ogi.state.ok.us/geoserver/wms? Click the Get Layers button If the connection is successful, click the OK button
In ArcMap: Click the Add Data button From the Look in: list, select GIS Servers If you already added a connection in ArcCatlog, select that connection, otherwise: Double-click Add WMS Server In the URL text box, enter http://ogi.state.ok.us/geoserver/wms? Click the Get Layers button If the connection is successful, click the OK button
To add a WMS layer to ArcMap: Double-click the WMS server in the GIS Servers list Double click GeoServer Web Map Server Double click GeoServer Web Map Server again Select the layer(s) from the list you wish to add Note: In 9.1 and below, you cannot add individual layers, only the entire service.

ArcGIS automatically performs the GetMap and GetFeatureInfo requests, thereby enabling you to not only to view map layers stored on a remote server, but also acquire attribute information about each feature in the selected layer(s).

Content is forthcoming.

Google Earth is a virtual globe designed for viewing a range of geographic features. With Google Earth, it is possible to add WMS overlays from various WMS-enabled Internet map servers.

Once Google Earth is launched: (Optional, but recommended) Zoom into the area of interest Select Image Overlay from the Add dropdown menu (Ctl+Shift+O) Enter a unique name in the Name text box (e.g. OGI) In the New Image Overlay window, select the Refresh tab Click the WMS Parameters button Click the Add... button next to the WMS Server dropdown list In the URL text box, enter http://ogi.state.ok.us/geoserver/wms? Once the connection parameters are set: Select the layer(s) you wish to add from the layers list Click Add-> button Click the OK button (Optional, but recommended) Set a Time-Based and View-Based refresh rate Click the OK button again

Though Google Earh has WMS support, OKMaps permits direct export of layers to a Google Earth format (KML).

ArcGIS Explorer is a free virtual globe/GIS viewer for visualization of geographic information.

To add WMS layers to ArcGIS Explorer:

Launch ArcGIS Explorer: Select Open from the File dropdown menu (Ctl+O) In the Open Content window, select Servers Click the WMS button In the Server text box, enter http://ogi.state.ok.us/geoserver/wms? Click the OK button Once the connection parameters are set: Expand the connection Select a raster cell size, then click the Next > button From the layers list, select the layer(s) you wish to add Click the arrow button to add it to the Layers to add list Click the Next > button Select the appropriate imagery format, then click the Next > button Select an appropriate disk caching option Click the Finish button

NASA World Wind is a virtual globe developed by NASA that provides support WMS overlays.

Once NASA World Wind is launched (and set to Earth viewer): Select Import WMS url to layer... from the Tools dropdown menu In the Enter WMS url: text box, enter http://ogi.state.ok.us/geoserver/wms? Click the Get WMS Tree button Once the connection parameters are set: Click the Save as XML button Close the WMS Importer window Click the Layer Manager Button Expand the WMS connection node Select the layer(s) you wish to draw

Quantum GIS (QGIS)is an Open Source GIS project of the Open Source Geospatial Foundation (OSGeo). QGIS runs on Linux, Unix, Mac, and Windows platforms and has built-in WMS support.

The instructions for adding a WMS layer to QGIS are based on version 1.0.2. "Kore" running on a Windows platform. Steps may vary with different versions and/or platforms.

In Quantum GIS: Click the Add WMS Layer button In the Add Layer(s) from a Server dialog window, click te New button In the Name tex box, enter a unique name for you connection(e.g. OGI) In the URL text box, enter http://ogi.state.ok.us/geoserver/wms? Click the OK button Once the connection parameters are set: Select the Server Connection from the dropdown list Click the Connect button Select the layer(s) you wish to add from the list Click the Add button

Quantum GIS automatically performs the GetMap and GetFeatureInfo requests, thereby enabling you to not only to view map layers stored on a remote server, but also acquire attribute information about each feature in the selected layer(s).

uDIG (or User-friendly Desktop Internet GIS) is an open source desktop application for Windows, Mac, and Linux. uDIG is designed to easily consume standard geospatial web services, such as WMS and WFS, and may be used as a stand-alone application or a plug-in to other Eclipse Rich Client (RCP) applications.

In uDIG: Select Add... from the Layer dropdown menu In the Data Sources window, select Web Map Server, then click the Next button In the URL text box, enter http://ogi.state.ok.us/geoserver/wms? Click the Next button Once the connection parameters are set: Select the layer(s) you wish to add from the list Click the Finish button

Once a WMS connection is established with uDIG, the map service should appear in the uDIG catalog list. To add addtional WMS layers from this service, expand the service and select the layers. uDIG automatically performs the GetMap and GetFeatureInfo requests, thereby enabling you to not only to view map layers stored on a remote server, but also acquire attribute information about each feature in the selected layer(s).

gvSIG is a free and open source desktop GIS designed for managing geographic data. gvSIG supports numerous vector and raster spatial data formats and can consume standard geospatial web services, such as WMS, WFS, and WCS.

In gvSIG: Open a View (Recommended) change coordinate system from UTM N Zone 30 to GCS WGS 84 (EPSG:4326)--see below Select Add Layer (Alt+O) from the View drop down menu Click the WMS tab In the Server text box, enter http://ogi.state.ok.us/geoserver/wms? Click the Connect button Click the Next button Once the connection is established: Select the Layers tab Select the layer(s) you wish to add Click the Add button Click the Formats Tab Select an image format (e.g. image/png) Select the correct SRS (spatial reference system)--all OKMaps vector layers are EPSG:4326 Click the OK button Note: gvSIG is a Spanish project and the default coordinate system for all new views is UTM Zone 30 N (EPSG:23030). It is highly recommended you change the View to GCS WGS 84 (EPSG:4326) or a more appropriate coordinate system for Oklahoma data prior to adding WMS layers from OKMaps.