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Lesson 5: using the national map web services in ArcMap.
In this lesson we will provide an overview and demonstrate how
to use the national maps web services in a mapping application.
Although downloading data from the national map is a popular option for many users,
there are numerous situations where it may be preferable to simply call T&M web
services into your mapping application.
By using the national map services, you can minimize data storage issues and
eliminate the need to download data on a regular basis to maintain currentness.
By the end of this lesson, you will be able to use the national map web services in a mapping
application by adding T&M services in an ArcGIS server rest service.
For this lesson, we will use ESRI's ArcGIS software.
USGS has an enterprise license agreement with ESRI and any USGS
staff can request a software license from the Enterprise GIS team within
the Office of Enterprise Information.
This abbreviated list of services shows the service URL's that
will be added to ArcMap in order to access the Basemap services.
Carter Overlay Services,
elevation overlay services,
and hydrography overlay services.
Please note that the USGS service URLs are subject to change.
Therefore please refer to this link to gather the most up-to-date service URLs.
apps.nationalmap.gov/services
The national map publishes over 49 services containing a variety of
basemaps and specialized GIS data.
Service URLs are case sensitive and all are available through the SSL
connection by using the https protocol.
Let's get started.
There are several ways to call T&M services and ArcGIS.
We will demonstrate a quick way to set up the usage of T&M services
in ArcMap so that the services are easily accessible for repeated use.
First locate the ArcMap program on your computer.
Open the application.
And begin with a new blank map.
Next, within ArcMap, click on the catalog icon.
This is the icon that looks like a file cabinet.
Then click the pushpin icon to pin the catalog pane open. In the catalog pane,
which has now appeared, locate the GIS servers.
In the catalog pane that has now appeared, click the GIS servers folder and expand
the folder by clicking on the plus sign.
Select add GIS server and then double click it.
In the pop up window that appears select use GIS services,
then click next.
Next, enter the server URL for TNM Basemap services,
which we referenced earlier.
Then click finish.
You can see a new entry has been added in the catalog for the base map services.
Click on the plus sign to expand and view the list of available layers.
These tilecached basemaps offer excellent performance across all scales.
From world to 1:9000 in a simple to use single layer map service.
To add one of these layers to your map,
drag and drop one of them from the catalog pane into the map pain.
Here we will add the USGS Topo service to the map.
The layers in the National Map services are scale dependent,
so the resolution will increase as you zoom in.
Returned to the catalog pane and add the carto overlay services
by following the same procedure.
Select add GIS server and double click it.
Select use GIS services and click next.
Then enter the carto service URL and click finish.
Expand the layer to see the available services with the carto overlay services.
Select a layer, then drag and drop it into the map pane.
Here we are adding a map indices layer.
Next, add the elevation overlay services URL and expand the layer.
Select the 3DEP elevation service layer, then drag and drop it into the map pane.
Lastly, let's add the hydrography overlay services URL.
This layers display is scale dependent and its features are
not shown at the national level.
First, let's turn off the elevation layer and map index and then
zoom into an area of interest.
Now add the hydrography overlay services URL and expand the layer.
Select the NHD services layer and drag and drop it into the map pane.
Let's turn off the USGS Topo layer and see the NHD layer alone.
Expand the NHD layer in the table of contents pane.
You can see that the NHD features that are visible in the current
scale have check marks in black, while features not visible in this scale have gray check marks.
Looking in the catalog pane at the list of services available at each URL,
you may notice what seems like duplicative layers among them,
and wonder which is preferable for you to use.
For example, you can see several different layers.
In general, the cachetile basemap services
provided at the base map URL, work well at scales from world to 1:9000.
If you are mapping at larger scales such as those below 1:9000,
Hydro overlay services are likely preferable to use.
Again, a complete list of the National Map service endpoints
is available at apps.nationalmap.gov/services
Further information on how to use the services is available through
the how to use link at the upper right of the web page.
If you have a particular interest in elevation data services,
you can learn more about the dynamic elevation web service in Lesson 10f.
The elevation map service creates multiresolution visualizations on
the fly and allows access to the underlying data for analysis and
visualization in GIS software.
If you use ArcGIS Pro or ArcGIS Online, there is an additional functionality
to the web service. Services such as NHD and WBD allow users to change labeling
and symbology as well as identify features.
To do this, expand the service and add the layers, not the whole
service that you want on your map.
The layers will load with the default symbology and can be changed to suit your needs.
In this lesson, we discussed how to use the National Maps web services in ArcMap.
We added four service URLs to ArcMap using
the add GIS servers function in catalog.
We expanded the services in catalog to see what layers are available.
And we demonstrated how to drag and drop layers from catalog into the map pane.
The National Map web services provides a quick and useful way to access the
most current National Map data for use in mapping applications without the
inherent limitations of downloaded data.