Acquire Elevation Imagery
NOTE: This exercise assumes you have completed the previous exercise.
This exercise teaches you to acquire free elevation data from the USGS to analyze with the Octopus app.
Acquire Elevation Data
- Start the Shell app. (Start » Programs » Scenomics » Shell) or (Windows® key and then type 'Shell' to find the app icon.)
The application displays a splash screen and then the application desktop appears.
Start a web browser (leave the Shell app running)
We need some elevation data. There are many sources and formats, but for now we'll focus on GEOTIFF elevation data that we can acquire from the United States National Map.
Load the following URL: https://apps.nationalmap.gov/downloader/#/
NOTE: In the image below, we've placed a red box around the area of interest: Washington State. You won't see this red box on your map, but this will help you know where to zoom in the next step.
Zoom in to Washington State, which is in the upper left corner of the continental United States.
NOTE: In the image below, we've placed a red box around the area of interest: Mt. Baker National Forest, near Bellingham, Washington State. You won't see this red box on your map, but this will help you know where to zoom in the next step.
- Zoom in to the Mt. Baker area, which is in the upper middle of Washington State, east of Bellingham, WA.
- Examine the product search and download options on the left side of the browser window.
Check the Elevation Products (3DEP) option.
This displays a list of elevation products.
- Left click the 1/3 arc-second DEM option.
Left click the blue Search Products button near the top-left of the products and download options area.
The National Map Viewer searches for available elevation imagery and displays the results. NOTE: We have highlighted the elevation data of interest with a red box. You won't see this red box in your search results. The desired data file refers to USGS 13 arc-second n49w122 1 x 1 degree.
Examine the search results and left click the option Download TIF option on the right column of the elevation data preview window.
NOTE: This file is about 500MB in size.
Your web browser presents a dialog that allows you to download the elevation data to your machine. The file will be saved to your downloads folder as USGS_13_n49w122.tif.
- Return to the running copy of the Shell application.
Select File » Open Application Directories from the main menu.
The software displays a list of directories to open.
Select the option that ends with \Library\Textures\Elevation.
The software opens a folder to this directory.
- Copy the GEOTIFF file USGS_13_n49w122.tif from your downloads folder into the elevation data directory we just opened.
- Close the folder containing the elevation data.
- Close your web browser if desired.
- Return to the running Shell application and select File » Exit from the main menu.
Please proceed to the next exercise.