Finding and accessing high quality elevation data can be challenging. If you're working in a coastal area, the NOAA Coastal Service Center's Digital Coast website will probably be one of your first stops. Not only does this website provide users with access to data collected by NOAA itself, but a variety of other data sources have shared data with NOAA, such as the United States Army Corps of Engineers.
The Digital Coast's Data Access Viewer features an intuitive way to search for and download a variety of data that address a range of topics, such as benthic, elevation, imagery, land cover and socioeconomic.
This tutorial focuses on downloading elevation data for a specific area. In this case, we'll focus on Fire Island National Seashore, which is a barrier island extending along the southern coast of Long Island, New York. If this is your first time visiting Fire Island, this URL will help you orient yourself.
First, go to the Digital Coast Data Access Viewer link. Next, select Elevation as the type of data you’d like to explore. Navigate to our area of interest (AOI) by either using the Search bar along the top left of the application, or manually zoom into the study area within the interactive map.
Once you locate the general vicinity of our AOI, use the Draw Search Area button to draw a box around the area. This selects all elevation data that fall within this area; the yellow box (see below) is the AOI featuring Fire Island, while the orange-shaded polygons represent the elevation data available in this area.
You should now see a listing of data collections along the right side of the application. If you hoover over the “2014 NOAA NGS Topobathy Lidar: Post Sandy (SC to NY)” collection at the top of the list, you will notice that the full extent of the data is shown on the interactive map in light blue (see below).
Click on the “2014 NOAA NGS Topobathy Lidar: Post Sandy (SC to NY)” collection top bring up more detailed information about the data, such as a brief description of the collection, who the data provider is, the nominal point spacing, available data classes and the vertical accuracy and the horizontal accuracy of the data. This tab also provides a direct link to the metadata.
Depending on the size of your AOI, you may notice that the “Add to Cart” option is greyed out; this is because the AOI contains too much data to easily export. Re-draw a smaller AOI so that you can add the data to your cart.
To begin downloading datasets, simply click the Add to Cart button at the top of the Data Detail area, select the Checkout button that appears in the top right corner of your web browser, which leads to a new checkout menu.
The first screen of the checkout process displays the items in your cart; ensure the proper data are reflected here and continue by clicking the Next button in the bottom right corner of the window. Now the Provision Your Data page becomes active. This is where the user may define how their selected data are exported. Let's explore these options some more.
First, select the Projection; for this example, we'll choose UTM. Leave the Zone dropdown as it (Zone 18 Range 078W-072W). You then need to select your Horizontal Datum and Horizontal Units. Choose units of meters. Select the Vertical Datum to be NAVD88. It is important to ensure that the Vertical Units (located below the horizontal units) are also selected as meters.
Next, head down to Output Options section. Select ‘point’ from the Output Product dropdown menu, and ‘Points – LAS’ from the Output Format dropdown menu. Under Data Options, select ‘All’ under the Data Classes menu.
Finally, click Next to move to the Delivery screen; here's the place to enter an email address to which a download link will be sent after your selected data have been prepared. After you've entered an email address, click next and double-check your order information. When satisfied that everything is correct click next to finish. Shortly, you will receive an email containing a confirmation message along with a link to check on the status of your data order. When the website has completed processing your data, you should receive a second email with a download link(s). Follow this link to download the data to your computer, and to begin working with these data for your own projects.
This blog posting was developed with the support of a competitive grant (cooperative agreement number P09AC00212; task agreement number P13AC00875) from the National Park Service in partnership with the North Atlantic Coast Cooperative Ecosystems Studies Unit.