National Atlas Web Map Services Introduction

We've recently updated our Web Map Services (WMS), and a brief description of the updated WMS follows. If you’re already WMS savvy, you might simply want to go to one of the step-by-step instructions below for viewing our WMS in popular mapping programs.
The National Map viewer
Esri ArcGIS
Intergraph GeoMedia
Google Earth
Quantum GIS

General Information About the WMS

• Technical details are on our National Atlas WMS page.
• All National Atlas vector map layers are available in this updated WMS.
• The National Atlas WMS currently supports GetCapabilities, GetMap, GetFeatureInfo, and GetLegendGraphic requests.
• The default projection for National Atlas WMS map files is EPSG:4326 (WGS 84).
• All map layers fit within -180, 0, 0, 90 (east, south, west, north).
• The National Atlas WMS defaults to WMS Version 1.3.0, so be sure to specify an earlier version if your viewer does not handle version 1.3.0 well.
• If you use ArcGIS 9.3.x, be sure to specify WMS version 1.1.1. or lower.
• Be sure to specify WMS version 1.1.1 for the National Map viewer, too.

Using the National Atlas WMS

Accessing the Capabilities File

You typically begin a WMS request by accessing the capabilities file for the map of interest. Since the National Atlas WMS currently contains over 2,400 individual layers, we have grouped the map layers' capabilities files into the broad categories that you will find throughout the National Atlas web site: Agriculture, Biology, Boundaries, Climate, Environment, Geology, History, Map Reference, People, Transportation, and Water. Use the online addresses in Table 1 to access the capabilities file for the categories of interest to you.

Category	URL	Size
1 Million-Scale Map Layers	http://webservices.nationalatlas.gov/wms/1million?SERVICE=WMS&REQUEST=GetCapabilities	41 KB
Agriculture	http://webservices.nationalatlas.gov/wms/agriculture?SERVICE=WMS&REQUEST=GetCapabilities	33 KB
Biology	http://webservices.nationalatlas.gov/wms/biology?SERVICE=WMS&REQUEST=GetCapabilities	1.55 MB
Boundaries	http://webservices.nationalatlas.gov/wms/boundaries?SERVICE=WMS&REQUEST=GetCapabilities	16 KB
Climate	http://webservices.nationalatlas.gov/wms/climate?SERVICE=WMS&REQUEST=GetCapabilities	100 KB
Environment	http://webservices.nationalatlas.gov/wms/environment?SERVICE=WMS&REQUEST=GetCapabilities	24 KB
Geology	http://webservices.nationalatlas.gov/wms/geology?SERVICE=WMS&REQUEST=GetCapabilities	51 KB
Government	http://webservices.nationalatlas.gov/wms/government?SERVICE=WMS&REQUEST=GetCapabilities	48 KB
History	http://webservices.nationalatlas.gov/wms/history?SERVICE=WMS&REQUEST=GetCapabilities	12 KB
Map Reference	http://webservices.nationalatlas.gov/wms/map_reference?SERVICE=WMS&REQUEST=GetCapabilities	12 KB
People	http://webservices.nationalatlas.gov/wms/people?SERVICE=WMS&REQUEST=GetCapabilities	456 KB
Transportation	http://webservices.nationalatlas.gov/wms/transportation?SERVICE=WMS&REQUEST=GetCapabilities	22 KB
Water	http://webservices.nationalatlas.gov/wms/water?SERVICE=WMS&REQUEST=GetCapabilities	144 KB
All Layers	http://webservices.nationalatlas.gov/wms?SERVICE=WMS&REQUEST=GetCapabilities	5.46 MB

Table 1: Summary of National Atlas Capabilities Files

Viewing the National Atlas WMS in The National Map Viewer

There are two ways you can view National Atlas layers using the National Map Viewer.

The "Search Box" Method

1. Navigate to The National Map Viewer at http://viewer.nationalmap.gov/viewer/
2. In the Search box at the top of the page, copy and paste one of the GetCapabilities URLs from Table 1. Be sure to append the version parameter to the URL (for example, "&version=1.1.1"). The version should be 1.1.1. Here is an example of a complete URL: http://webservices.nationalatlas.gov/wms/agriculture?SERVICE=WMS&REQUEST=GetCapabilities&VERSION=1.1.1
3. Click the Search button (or press the Enter key).
4. In the Overlays panel, expand the category headings to view the list of layers, and check or uncheck the desired layers.

The "Add Data" Method

1. Navigate to The National Map Viewer at http://viewer.nationalmap.gov/viewer/
2. Click on the Advanced tab.
3. Click on the Add Data button.
4. Click on the WMS button.
5. Copy and paste one of the GetCapabilities URLs from Table 1. Be sure to append the version parameter to the URL (for example, "&version=1.1.1"). The version should be 1.1.1. Here is an example of a complete URL: http://webservices.nationalatlas.gov/wms/agriculture?SERVICE=WMS&REQUEST=GetCapabilities&VERSION=1.1.1
6. Click the Add Data button.
7. In the Overlays panel, expand the category headings to view the list of layers, and check or uncheck the desired layers.

Viewing the National Atlas WMS in Esri ArcGIS

1. Open a new project in ArcMap.
2. Click the ArcMap Add Data command button.
3. Select GIS Servers from the Add Data Dialog drop-down list.
4. Select Add WMS Server and click Add.
5. Copy and paste one of the GetCapabilities URLs from Table 1 and if you use ArcMap 9.3.x be sure to specify WMS version 1.1.1 or lower.
6. Click the Get Layers button, and then click OK.
7. In the Add Data dialog, click Add.
8. Select the Layers and click Add again.
9. ArcMap turns on all layers by default. Turn off layers as needed.

To Identify Feature Information in ArcMap:
Click the Identify tool on the Tools toolbar to enable, then click on a point on the map to get feature information. In the Identify window, it is recommended that you use the 'Identify from' drop-down list to select the WMS layer you are interested in identifying or use the <Visible Layers> option.

To View the Legend in ArcMap:
In the Layers panel, right-click on the name of the map layer and select 'Add WMS Legend to Map.'

Viewing the National Atlas WMS in Intergraph GeoMedia

1. Open a GeoWorkspace in GeoMedia.
2. Under the Warehouse menu,click the New Warehouse Connection command option.
3. In the Connection type list, find the WMS option and select it. A new set of connection parameter fields will be displayed.
4. In the Web Map Service (WMS) URL field, copy and paste one of the GetCapabilities URLs from Table 1 and be sure to specify WMS version 1.1.1. Here is an example of a complete URL: http://webservices.nationalatlas.gov/wms/agriculture?SERVICE=WMS&REQUEST=GetCapabilities
5. Click OK to make the connection.
6. Under the legends menu, click Add Legend Entries.
7. Select the appropriate Layers from the tree view and click OK.
8. The layers will then be displayed in the Map View.

Viewing the National Atlas WMS in Google Earth

1. Position the 3D viewer in the location where you want to place the overlay image file.
2. Click Add > Image Overlay or click the Image Overlay button. The New Image Overlay dialog box appears.
3. In the New Image Overlay dialog box, click the Refresh tab.
4. Click WMS Parameters. The Web Mapping Service Parameters dialog box appears.
5. Click the Add button at the top of the Web Mapping Service Parameters dialog box, next to the WMS Server drop down list.
6. Copy and paste one of the GetCapabilities URLs from Table 1 (for example "http://webservices.nationalatlas.gov/wms/agriculture?SERVICE=WMS&REQUEST=GetCapabilities"). Click the OK button. After a brief period of time, Google Earth populates the Opaque and/or Transparent Layers fields with available layers.
7. Choose the appropriate layer(s) and click Add -> to add the layer(s) to the Selected Layers field. This places the selected layers in the WMS image overlay you will see in Google Earth. To remove a layer from the Selected Layers field, select it and click <-Remove.
8. To set the order of selected layers as they appear in the 3D viewer, select the appropriate layers in the Selected Layers field and click Move Up or Move Down.
9. When you are finished, click OK.
10. In the Link text box (in the New Image Overlay dialog), verify that Transparent=TRUE and the image type is set as png.
11. Enter a descriptive name in the name field and specify the descriptive information for the overlay. Specify other characteristics as needed. When you are done, click OK.

Viewing the National Atlas WMS in Quantum GIS

1. Select Add WMS Layer... from the Layer menu. This will display the Add Layer(s) from a Server dialog box.
2. In the Layers tab, click the New button. This will display the Create a New WMS connection dialog box.
3. Enter a descriptive name in the Name text box.
4. In the URL text box, copy and paste one of the GetCapabilities URLs from Table 1 (for example "http://webservices.nationalatlas.gov/wms/agriculture?SERVICE=WMS&REQUEST=GetCapabilities").
5. Click the OK button to add the new connection.
6. In the Add Layer(s) from a Server dialog box, click the Connect button.
7. Select the layer(s) you want to add, and then click the Add button.
8. When you are done adding layers, close the Add Layer(s) from a Server dialog box by clicking the Close button.

To Identify Feature Information in Quantum GIS:
Click the Identify tool to enable, then click on a point on the map to get feature information. The results will be returned as plain text in a pop-up window.

Plans for the National Atlas WMS

• Introducing an experimental Web Feature Service.
• Assessing user interest in Web Coverage services.
• If you have quick and easy instructions for using National Atlas WMS in your map viewer or application, please let us know.