Aquaveo & Water Resources Engineering News

Downloading NLCD Data

One of the crucial elements of any project is having data. WMS makes use of a large number of data sources. One type of data that we find frequently used is National Land Cover Database (NLCD) data. NLCD is provided by the MRLC (Multi-Resolution Land Characteristics Consortium) as a large collection of raster datasets.

Here are three ways this data can be imported into WMS.

Direct Download

NLCD data can be downloaded from the MRLC site. Much of the other data available on the MRLC site can also be used with WMS.

Downloaded NLCD data can be opened in WMS by selecting the Open macro, browsing to the folder containing the downloaded data, and selecting the desired raster. WMS should be able to recognize the data file and bring it into your project.

Using the Modeling Wizard

NLCD data can also be downloaded while using the Hydrologic Modeling Wizard or the HY-8 Modeling Wizard. To do this:

  1. Start the Hydrologic Modeling Wizard or the HY-8 Modeling Wizard
  2. Create the project in the first step
  3. Define your project bounds and set the project projection
  4. In the Watershed Data step, turn on the Use web services option
  5. In the Download Data (Web Services) step, select one of the NLCD data types
  6. Click the Download Data From Web button to download and import your NLCD data
  7. Enter a raster cell size for the data
  8. Save the data as a file
Using the Get Data Tool

Downloading NLCD data can also be obtained by using the Get Data tool. To use this tool, your project must have a projection already defined. When you have a projection set, do the following:

  1. Using the Get Data tool, click-and-drag a box in the Graphics Window that covers the area where you want NLCD data
  2. Save a file with the NLCD data
  3. Enter the raster cell size for the data
Downloading NLCD data

You might also notice that a lot of other data sources are available through the Modeling Wizard and Get Data tool. Feel free to try downloading data from these sources for your WMS projects.

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Using the Plot Data Coverage

Have you generated a plot in SMS and found it was difficult to see where a bridge, culvert, or other structure location matched up with the plot? The Plot Data coverage helps make them more visible, making an observation coverage more meaningful in a profile plot.

Typically, a profile shows some desired value such as water surface elevation or the riverbed elevation. This data can be more useful in many cases if structures are displayed on the plot as well. A Plot Data coverage allows creating polygons over structures that then helps display the location of the structure on the plot profile.

To use the Plot Data coverage, do the following:

  1. In the Map Module, create a new coverage with the Plot Data type.
  2. In this new Plot Data coverage, create a polygon over the area of interest.
  3. Double-click on the Polygon to assign attributes in the Plot Data dialog.
  4. Create an observation arc that includes the area of interest.
  5. Create an observation profile plot.
  6. In the Plot Data Options, turn on the Plot Data coverage.

The profile plot will now show where the polygon on the Plot Data coverage aligns with the profile.

Example of a Plot Data coverage used in a plot profile

For example, if you want to consider the impact of a new bridge placement on the flow of a river, you could create a polygon representing the bridge location. When included in the profile, this could help you visualize placing a bridge at that location along the river and at the indicated height. If water elevation data is available, such as from an SRH 2D simulation, the height of the bridge can be easily compared with elevation profile of the water surface. This could be helpful in considering if the bridge would be washed out or flooded during periods of heavy rain when the river swells.

Culverts can similarly be shown on the profile by using the Plot Data coverage. Likewise, obstructions or structures of any shape could also be shown in the profile using the Plot Data coverage. Multiple plot data coverages could be used when there is a desire to layer structures such as a hypothetical bridge and the supporting abutments or columns.

Try out using the Plot Data coverage in SMS today!

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