Module 6- Cartography- Isarithmic Map

 For this week’s exercise we focused on two methods of presenting data on an isarithmic map: continuous and hypsometric. We used PRISM annual precipitation data obtained from the USDA NRCS National Geospatial Management Center in coordination with the PRISM Group at Oregon State University for the state of Washington from 1981-2010.

First, we created a map presenting the precipitation data in continuous form. We also created our own hillshade layer to add to our map display elevation since this effect hasn’t been added to ArcGIS pro yet. Then we created a second map in which we converted the data to a hypsometric tint to better visualize the precipitation totals. To do this we used the Int (Spatial Analysis) tool to convert the raster data to integers. We then created 10 manual intervals to classify the data. We added our hillshade layer and added contour lines using the Spatial Analysis Contour List to add contour values. Finally, we were tasked to create a map layout and to include a description of how the data was interpolated.

When reviewing the differences in the continuous and hypsometric maps and answering the process summary questions I was reminded of a recent map I’d viewed on my local weather station’s website. Sure enough, both the tornado risk and predicted precipitation totals were shown on a hypsometric isarithmic map similar to the one I created.