Lab 6: Digital Elevation Models

     In this laboratory, we used data from the USGS National Map Seamless Server to create digital elevation models (DEM) using ArcMap and ArcScene.  The area selected extended from 37.025° N (bottom) to 37.28° N (top) and 119.072° W (left) to 118.774° W (right).  Therefore, the area shows a 0.255° spread in latitude and a 0.298° spread in longitude.  The coordinate system used for this exercise was the GCS North American 1983 and the corresponding datum was the D North American 1983.  Below are the maps created from this landscape:

MAP 1:  The color-ramped DEM layered above a hillshade

MAP 2: Slope Map

 

MAP 3: Aspect Map

 

MAP 4: Three-dimensional Representation

     Analysis of these four images allows for a comprehensive understanding of the selected area.  In Maps 1 and 4, the bluer regions correspond to higher elevations while the redder regions correspond to lower elevation.  This gradient shows the range of elevation in the selected area.  As seen in Map 2, the slope inclincation was relatively consistent throughout the entire area, as indicated by the overwhelming periwinkle, with a value of approximately 88°.  The aspect map shows the direction of the range's slopes, and the majority of blue/turquoise coloration indicates that the slopes were facing to some degree between south and west.  Futhermore, the 3D graphic clearly shows the topography of the area and the substantial differences in elevation.