Isarithmic Mapping

For lab this week, we were tasked with creating an Isarithmic map of annual precipitation for the state of Washington.  We used annual precipitation data that was interpolated using PRISM from Oregon State University.  We used this data to create a hypsometric tinted map with contour lines and the hill shade effect to give a visual interpretation of annual rainfall and elevation within the state.  To create the hypsometric tint, we used the Int (Spatial Analyst Tool).  We then made contours with the contour list tool and matched the contours with our tinted areas.  This reinforces the visual effect of clear delineations of changes in annual precipitation.  We used the Esri provided precipitation color scheme to provide contrast and clear understanding.  On this map, the precipitation ranges from 10 inches or less, to 261 inches of rain per year.  Red represents the low end of the spectrum and blue represents the high end of the spectrum.  The legend indicates this with a continuous scale so as to be congruent with the notion of continuous data.

I personally enjoyed this lab because it is similar to what I used to do with ArcGIS and incorporates much of the data types and analysis that I love to work with.  The specific tools were new to me, but it just reinforces the power of ArcGIS as an analytical tool.