Isarithmic Mapping of a 30 Year Period of the Precipitation in the State of Washington

 Here we are in Module 6, strengthening our cartography skills. This week we were tasked with making a Isarithmic map using continuous data of a 30-year period (1981-2010) of the precipitation in the state of Washington. The data used for creating this map was prepared using the PRISM interpolation method. The PRISM system was developed and used by the PRISM climate group at Oregon State University. PRISM calculates weather and climate variables, such as elevation, temperature, precipitation, rain shadows, coastal effects and more and uses nearby station data to populate the regression function then weights the station data points to control for the effects of a wide variety of physiographic variables. Calculating variables on a grid of millions of pixels, each measuring about 0.5 miles across the lower 48 states, daily, monthly and yearly. The PRISM system is the most widely used spatial climate data sets in the United States.

Some of the learning outcomes of this week's lab included an understanding of the PRISM Interpolation Method, understanding the use of continuous tone symbology and hypsometric tinting symbology. Being able to manually classify data and creating contours using the Contour List Tool. Learning how to utilize the Spatial Analyst Extension. These are just some of the tools and methods that we dove into.

The map I have presented here I made completely in ArcGIS Pro. The data was given to me from UWF that was downloaded from USDA Geospatial Gateway. We used the 30-year period of the average annual precipitation in inches (1981-2010). The data was already presented with a stretched color symbolization, which is continuous tone. A few adjustments were still needed to be made. I made the adjustment by changing the symbology color scheme to precipitation. Then I added the Hillshade effect relief using the Raster Function in the Analysis tab. Then using the Dynamic Range Adjustment I adjusted the continuous color scheme by changing the color values, which allowed for more relief. This is to help see elevation. I used the Int (Spatial Analyst Tool) To create the Hypsometric Tint layer to the map and then manually classified the data into 10 classes and symbolized it with the precipitation color ramp. Lastly before completing my map in Map Layout, I added a contour overlay by using the Contour List Spatial Analyst Tool. I then went to work creating all the final touches, finding a balance orientation of the data that was being presented and adding all the map essential elements using the visual hierarchy. All that was left was to share with all of you, enjoy!