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The following pages display collections of graphs for each of the study areas used in this research. For the Bakersfield-west and Los Angeles-west areas, four plots are presented on each page. The plot in the upper right corner is a histogram of the 3 arc second elevations for the quadrangle. The pronounced spiking in each of these graphs occurs at elevations corresponding to the contours in the source maps. The plot in the lower right displays the relationship between the 3 arc second elevations for the quadrangle on the x-axis, and the elevations derived from the 30m DEM on the y-axis. Although the trend in most of these plots is linear and follows a 1:1 relationship between the two, the point cloud can be quite wide. Additionally, spiking apparent from the histogram manifests itself in this graph. The plot in the upper left portrays the relationship between the 3 arc second elevation values and the difference between the two DEMs. Values above zero indicate points for which the 3 arc second elevation was higher than the 30m elevation, while points below zero are lower in the 3 arc second data than they are in the 30m data. Some of these plots indicate trends in the differences between the contour "spikes". This relationship is plotted in the graph on the lower left. Elevations are translated to a 61 meter range and matched against the difference between the two DEMs. A weak upward trend is apparent in all cases.

The Death Valley 3 arc second DEM did not suffer from this spiking problem. For quadrangles falling in this DEM, both the histogram of 3 arc second elevations and the relationship between 3 arc second and 30m DEMs are displayed. Again, the relationship is linear, with larger spread around the 1:1 line at higher elevations. Note that two of the quadrangles contain elevations below sea level.