Lab 06. Manipulating DEMs

When we were assigned this lab, we were told to pick an area with a lot of vertical relief. So, of course I had to choose the Grand Canyon. The Grand Canyon is not hard to find on a map of the U.S. Using the Seamless USGS DEM data downloader I scanned the Southwest until  I came upon a gigantic gash. Just to be sure it was the Grand Canyon and not some other gigantic rift in the middle of the country I hadn’t heard about, I brought up Google Earth and put in the Lat/Long from Seamless. As Google Earth performed a flyover I could make no mistake in identifying the location as the Grand Canyon. Aside from the enormous amount of geotagged vacation photos, there is such a massive elevation change in a small, compact area that there was no doubt in my mind of the identity of the feature. Examining the 3D representation of the canyon I’ve created, you can see the elongated cliff face and associated dramatic elevation drop. In the slope map, a ring of red bounding the canyon floor delineates a 90 degree slope, i.e. cliff face. In the color-ramped DEM the cliff edge can be seen as the elevation drops from high (red) to low (turquoise) within a matter of pixels. Interestingly, there is also a miniature canyon that eventually runs into the larger feature.

Specifically the area I chose was bounded by (in decimal degrees):

West: -112.182500
East: -111.592500
North: 36.323333
South: 35.887500
North American 1983 is the geographic coordinate system (GCS) utilized by the DEM.
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