Introduction to the 1 Experimental Web Feature Service

In the summer of 2012 we introduced 1, our new set of digital cartographic frameworks at one million-scale for mapping professionals. 1 is described in greater detail in this brochure. You can download 1 at no cost or freely connect to it as a Web Map Service (WMS) that complies with the current specification of the Open Geospatial Consortium (OGC).

Now we've made 1 available as the first National Atlas Web Feature Service (WFS). You can think of this as a read-only service that allows you to find, get, and use 1 spatial features without supporting transactions that modify these features. You may, of course, edit or spatially analyze the 1 features that we deliver to you. Our WFS supports these operations:

• GetCapabilities — discover 1 feature types and operations,
• DescribeFeatureType — learn about 1 features, and
• GetFeature — get only the 1 features you need for your area of interest.

What follows are detailed instructions for using the WFS in the popular Intergraph GeoMedia and Esri ArcGIS programs. We recommend a visit to our 1 Web Feature Service Technical Information page, too. If you have similar quick and easy instructions for using the 1 WFS from the National Atlas in your map viewer or application, please let us know.

Plans for the 1 WFS from the National Atlas

• We will add additional map layers to the WFS.
• Updates are reported by Twitter.
• A voluntary survey will be posted to learn more about the way you use the WFS and what we might do to improve the service.

Using the 1 WFS from the National Atlas
	General Information About the 1 WFS 1 WFS Boundaries Layers 1 WFS Transportation Layers	Using the 1 WFS in Intergraph GeoMedia Using the1 WFS in Esri ArcGIS 10.0 Using the1 WFS in Esri ArcGIS 9.3

General Information About the 1 WFS

• Only 1 map layers are available in this service. You can connect to all National Atlas map layers using our WMS.
• The default projection for National Atlas Web Feature Service map layers is EPSG:4269 (NAD 83).
• All map layers fit within -180, 0, 0, 90 (west, south, east, north).
• We support OGC WFS Version 1.1.0.

1 Web Feature Service Layers

The table below describes the available 1 Web Feature Service layers.

Map Layer	Web Feature Service Request	Web Feature Service URL	Size	Metadata
Congressional Districts of the United States - 113th Congress	GetFeature	http://webservices.nationalatlas.gov/arcgis/services/cgd113p010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetFeature&TypeName=cgd113p010g	63.2 MB	View metadata
	GetCapabilities	http://webservices.nationalatlas.gov/arcgis/services/cgd113p010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetCapabilities
	DescribeFeatureType	http://webservices.nationalatlas.gov/arcgis/services/cgd113p010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=DescribeFeatureType

Map Layer	Web Feature Service Request	Web Feature Service URL	Size	Metadata
Airports	GetFeature	http://webservices.nationalatlas.gov/arcgis/services/airprtx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetFeature&TypeName=airprtx010g	984 KB	View metadata
	GetCapabilities	http://webservices.nationalatlas.gov/arcgis/services/airprtx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetCapabilities
	DescribeFeatureType	http://webservices.nationalatlas.gov/arcgis/services/airprtx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=DescribeFeatureType
Ports	GetFeature	http://webservices.nationalatlas.gov/arcgis/services/portsx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetFeature&TypeName=portsx010g	162 KB	View metadata
	GetCapabilities	http://webservices.nationalatlas.gov/arcgis/services/portsx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetCapabilities
	DescribeFeatureType	http://webservices.nationalatlas.gov/arcgis/services/portsx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=DescribeFeatureType
Railroad and Bus Passenger Stations	GetFeature	http://webservices.nationalatlas.gov/arcgis/services/amtrakx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetFeature&TypeName=amtrakx010g	708 KB	View metadata
	GetCapabilities	http://webservices.nationalatlas.gov/arcgis/services/amtrakx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetCapabilities
	DescribeFeatureType	http://webservices.nationalatlas.gov/arcgis/services/amtrakx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=DescribeFeatureType

Table 1: 1 WFS layers.

Using the 1 WFS 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 WFS Read-only option and select it. A new set of connection parameter fields will be displayed.
4. In the Web Feature Service (WFS) URL field, copy and paste one of the GetCapabilities URLs from the WFS layers table above and be sure to specify WFS version 1.1. Here is an example of a complete URL for airports: http://webservices.nationalatlas.gov/arcgis/services/airprtx010g/MapServer/WFSServer?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetCapabilities
5. Click OK to make the connection.
6. Under the legends menu, click Add Legend Entries.
7. Select the appropriate Feature Types from the tree view and click OK.
8. The feature types will then be displayed in the Map View.

Using the1 WFS in Esri ArcGIS

Below are instructions for using the 1 WFS in ArcGIS 10.0 and ArcGIS 9.3.

Using the1 WFS with ArcGIS 10.0

Note: To connect to any Web Feature Service, you MUST have the Data Interoperability Extension installed. The Data Interoperability Extension is not typically part of the default installation of ArcGIS, so you may need to go back to your installation media and install the extension separately. Esri does not require a separate license for using the Data Interoperability Extension; you can install and use the Data Interoperability Extension without a separate license.

1. First, check that the ArcGIS Data Interoperability Extension is installed. In ArcCatalog, select Extensions from the Customize menu. In the Extensions dialog, make sure that the Data Interoperability extension is included in the list.
   
   If you don't see the Data Interoperability Extension in the list, you will need to install it. Consult your information technology staff for assistance; you may need to obtain the original ArcGIS installation media.
2. Once you have verified that the Data Interoperability Extension is installed, you may use the extension with or without a separate license for it.
   
   If you DO have a separate license for the Data Interoperability Extension, check the Data Interoperability Extension check box to enable full functionality of the extension and close the dialog.
   
   If you DO NOT have a separate license, leave the check box next to Data Interoperability Extension unchecked and close the dialog. You can connect to Web Feature Services without a separate Data Interoperability Extension license.
3. In ArcCatalog's Catalog Tree, expand the Interoperability Connections item. Then double-click the Add Interoperability Connection item. The Interoperability Connections dialog will appear.
4. In the Interoperability Connections dialog next to the Format box, click the "..." button. This will open the Formats Gallery dialog.
5. In the Formats Gallery dialog, read through the list of formats and single click on the row for WFS. Click OK to select the WFS format and return to the Interoperability Connection dialog.
6. Leave the Coordinate System as the default option ("Read from source").
7. In the Interoperability Connection dialog, click the Parameters button. This will open the WFS Parameters dialog.
8. Under WFS Connection in the URL text box copy and paste one of the GetFeature Request URLs from the WFS layers table above.
9. Under Constraints next to the Table List text box click the "..." button. This will open the Select Feature Types dialog.
10. In the Select Feature Types dialog, check the layer you want to add, then click OK.
11. (Optional) If you would like to restrict the results to a specific geographic region, check the Use Search Envelope check box. Then enter the coordinates in the Search Envelope Min and Max text boxes. All layers use the EPSG:4269 (NAD 83) projection. All layers fit between the following coordinates:
    Min X: -180
    Min Y: 0
    Max X: 0
    Max Y: 90
    If you use the EPSG:4326 (WGS 84) spatial reference system, map coordinates are ordered by latitude, longitude (y,x) in the WFS 1.1 specification, so be sure to also set the SRS Axis order to "2,1."
12. (Optional) If you would like to restrict the total number of features returned, use the Max Features text box in the Constraints section. Enter the maximum number of features you would like returned.
13. (Optional) To filter the results using the WFS filter parameter, use the XML Filter Expression text box in the Constraints section. The text must be an XML-formatted string containing the filter query. Because the filter string can be long, you can use the "..." button next to the XML Filter Expression text box to open a dialog that will allow you to edit the filter string in a larger text box. Table 4 and Example 5 on the WFS Technical Information page briefly describe the filter parameter. For more information on constructing a filter query, see the OGC Filter Encoding Specification for details.
    
    Example: In the airports map layer, there is an attribute named "ELEV" that contains the elevation value, in feet above sea level, for each airport. To retrieve only those airports with an elevation of 7,000 feet or greater, enter the following XML Filter Expression:
    
    <ogc:Filter xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/ogc/filter/1.0.0/filter.xsd http://www.opengis.net/gml/2.1/geometry.xsd">
    <ogc:PropertyIsGreaterThanOrEqualTo>
    <ogc:PropertyName>ELEV</ogc:PropertyName>
    <ogc:Literal>7000</ogc:Literal>
    </ogc:PropertyIsGreaterThanOrEqualTo>
    </ogc:Filter>
14. In the WFS Parameters dialog, click OK.
15. In the Interoperability Connection dialog, click OK to add the new connection. Your new WFS connection will now appear under Interoperability Connections.
16. ArcCatalog gives WFS connections a default name such as "Connection (1) - WFS". You will probably want to rename this connection to something more descriptive so you can identify it later in step 20.
17. Close ArcCatalog. Open ArcMap and create a new blank map.
18. Click the ArcMap Add Data command button.
19. Select Interoperability Connections from the Look In drop-down list.
20. Select the WFS connection you created in step 16 and click Add. Note: some layers may take a long time to load.

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 WFS layer you are interested in identifying or use the <Visible Layers> option.

Using the1 WFS with ArcGIS 9.3

Note: To connect to any Web Feature Service, you MUST have the Data Interoperability Extension installed. The Data Interoperability Extension is not typically part of the default installation of ArcGIS, so you may need to go back to your installation media and install the extension separately. Esri does not require a separate license for using the Data Interoperability Extension; you can install and use the Data Interoperability Extension without a separate license.

1. First, check that the ArcGIS Data Interoperability Extension is installed. In ArcCatalog, select Extensions from the Tools menu. In the Extensions dialog, make sure that Data Interoperability extension is included in the list.
   
   If you don't see the Data Interoperability Extension in the list, you will need to install it. Consult your information technology staff for assistance; you may need to obtain the original ArcGIS installation media.
2. Once you have verified that the Data Interoperability Extension is installed, you may use the extension with or without a separate license for it.
   
   If you DO have a separate license for the Data Interoperability Extension, check the Data Interoperability Extension check box to enable full functionality of the extension and close the dialog.
   
   If you DO NOT have a separate license, leave the check box next to Data Interoperability Extension unchecked and close the dialog. You can connect to Web Feature Services without a separate Data Interoperability Extension license.
3. In ArcCatalog's Catalog Tree, expand the Interoperability Connections item. Then double-click the Add Interoperability Connection item. The Interoperability Connection dialog will appear.
4. In the Interoperability Connections dialog next to the Format box, click the "..." button. This will open the Formats Gallery dialog.
5. In the Formats Gallery dialog, read through the list of formats and single click on the row for WFS. Click OK to select the WFS format and return to the Interoperability Connection dialog.
6. Leave the Coordinate System as the default option ("Read from source").
7. In the Interoperability Connection dialog, click the Settings button. This will open the Web Feature Service dialog.
8. Under WFS Connection in the URL text box copy and paste one of the GetFeature Request URLs from the WFS layers table above. Note: if you would like to reduce the number of results that are returned, you can append parameters such as BBOX (limits the results to a geographic bounding box) or maxfeatures (limits the total number of results) to the GetFeature request. See Table 4 on the WFS Technical Information page for more information on supported parameters.
9. Under Constraints next to the Table List text box click the "..." button. This will open the Web Feature Service (WFS) Table List dialog.
10. In the Web Feature Service (WFS) Table List, check the layer you want to add, then click OK.
11. In the Web Feature Service (WFS) Settings dialog, click OK.
12. In the Interoperability Connection dialog, click OK to add the new connection. Your new WFS connection will now appear under Interoperability Connections.
13. ArcCatalog gives WFS connections a default name such as "Connection (1) - WFS". You will probably want to rename this connection to something more descriptive so you can identify it later in step 17.
14. Close ArcCatalog. Open ArcMap and create a new empty map.
15. Click the ArcMap Add Data command button.
16. Select Interoperability Connections from the Look In drop-down list.
17. Select the WFS connection you created in step 13 and click Add. Note: some layers may take a long time to load.

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 WFS layer you are interested in identifying or use the <Visible Layers> option.