GEOG 5121 Project 3: Acquiring Geographic Data
Raleigh West, North Carolina Quadrangle
John Taber

Figure 1: Digital Elevation Model
This image shows the elevation in the Raleigh West, North Carolina 7.5-minute quadrangle (35.75 to 35.875 degrees North, 78.625 to 78.75 degrees West).  It was derived from data downloaded from the USGS Global Land Information System (WebGLIS) and processed in DLG Viewer version 3.7 using the HSV shader.  UTM projection datum is NAD27 in zone 17.  Elevation ranges from 51 to 159 meters.

The red valley across the north is Crabtree Valley, formed by Crabtree Creek.  The turqoise lake near the southwest corner is Lake Johnson; less apparent, a bit to the east (in green) is Lake Raleigh.  Lynn Lake is in the northwest corner, and Shelley Lake near the northeast corner.  The latter can be found by following major tributary (Big Branch Creek) from Crabtree Creek  Now that this area has been (largely) paved over, the differences in elevation shown by this image are not readily apparent from the ground.

Figure 2: Digital Line Graph
This image shows five layers of vector data derived from USGS topographic maps for the same study area.  It, too, was processed in DLG Viewer from data downloaded from WebGLIS.  Boundaries are in white, hydrology is blue, pipelines are gray railroads are pink, and roads are orange.  Areas are represented by triangles, and nodes with squares.  (These have been removed from the roads layer for clarity.)  The less built-up area in the northwest is part of Umstead State Park, now surrounded by development.  Interstate 40 begins with the interchange on the western edge, and arcs south across to the southern part of the map.  Interstate 440 begins at the southwest corner, heading northeast across the center of the map before turning east.  The railroad yards in the old industrial area of Raleigh are near the eastern edge.

Figure 3: Digital Orthophoto Quadrangle
This image shows an orthophoto, or digitally reconciled aerial view, of the northwest part of the study area.  It was downloaded from WebGLIS as a TIFF file and converted for this project.  (Cost was $7.50.)  This image was created in 1995, and unlike Figures 1 and 2, uses the 1983 projection of the North American Datum.  The interchange where Interstate 40 enters Figure 2 on the western edge is prominently shown on the southwest corner of this image.  Umstead Park takes up the western part of the image.  Lynn Lake can be seen at the northwest corner.

Figure 4: Digital Raster Graphic
This image shows the information found on the USGS topographic map for the study area, in raster form.  This file was download from WebGLIS for the cost of $1.00, and converted from TIFF format.  This image was created in 1999, and also uses NAD83.  Urbanized areas are in pink, forests in green.  The four lakes noted in Figure 1 can all be easily seen here, as well as others.

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