GIS 3015: Isarithmic Mapping

Our assignment this past week was to create an isarithmic map showing the annual precipitation of the state of Washington.  I created a map showing both continuous tone (not shown) and hypsometric tints (shown below).  The addition of hypsometric tints between contour lines enhances the ability to visualize a 3-D surface because light and dark tints can be associated with low and high values. The problem with this method, though, is that the limited number of tones suggests a stepped surface, rather than a smooth one that occurs in reality.  This issue can be fixed by creating a continuous tone map, which each point on the surface is shaded with a gray tone (or color) proportional to the value of the surface at that point.  However, one problem with interpreting continuous tone maps is that it is difficult to associate numbers in the legend with particular locations, but this can be fixed by using hypsometric tints (as shown below) which overlays continuous tones with traditional contour lines.