Friday, July 24, 2015

Add a Web Mapping Data Service to ArcMap

I have a hole in my current coverage of waterbodies - I need to know the name of a few streams, and the dataset of Rivers doesn't include the stream I need. I don't necessarily want to download and manage another whole dataset of flowing waters. Temporarily referencing a Web mapping service in my ArcMap project would be great.

The best database I am aware of that includes comprehensive waterbody geometry and names is the USGS's National Hydrography Dataset. Thankfully, they do indeed provide a Web mapping service!

Search for a Mapping Service

A quick Google search with the phrase nhd web map returns a direct link to the USGS National Map's map service endpoint:

http://services.nationalmap.gov/arcgis/rest/services/nhd/MapServer

  • Copy this URL from the browser for use in the next section
These Map or Feature Service URLs (referred to as "service endpoints" or simply "endpoints") aren't always so easy to find, so other projects/data services may require more digging. Look for clues in the URL itself such as the /rest/services/ directories, and for minimal styling (basic-looking fonts, colors, lists, etc.).

To link to a specific portion of the map service (for instance a specific layer or layer group within the main service layer), follow some of the links under the Layers list (see below). Copy that specific URL for use in the next step if you would like. Compare the following URL that represents the Waterbody layer which is layer position 11 in the service package:




Add a Service to ArcMap

  1. Click the Add Data button 
  2. Change the Look in category to GIS Servers

  1. Double click on Add ArcGIS Server to launch the Add ArcGIS Server wizard
  2. Accept the default value to simply Use GIS services and click Next
  3. Paste the Server URL that was copied from where you found the chosen service endpont
  4. Leave the User Name and Password blank if the server is open for public use, and click Finish

Adding the Service Layer to an ArcMap Project

  • Hit the Add Data button again if you aren't already there
  • Ensure your Look In category is pointing to GIS Servers, just as we did in the last section
  • Double click on NHD on services.nationalmap
! Note: Slow double click on this element to rename this to "National Hydrography Dataset" or anything else if you don't prefer this title

  • Double click the nhd service layer to add the dataset to your project
! Note: This is a large dataset with that's referencing a ton of layers and information. Depending on the speed of your computer, your network connection, and the size of your existing ArcMap project, it may take some time for the layer to be added to your project.


Structure of the NHD map service. Notice that scale-
dependent drawing is set for a number of layer groups.

1 comment:

Drew said...

Very nice step-by-step process document.