Making Maps: Module 8 - Isarithmic Mapping

This week we spent some time learning about isarithmic maps, which are a type of map used to display continuous data. As an avid hiker and user of topographic maps, I enjoyed learning a bit more about how contour lines are created through data interpolation. While interpolation methods and mathematical functions are a bit confusing, the concept was pretty understandable once I watched the lecture videos (thanks to our professor for putting it in layman's terms).

The lab assignment consisted of creating two maps, one with continuous tone values and one with hypsometric tinting, using annual precipitation data for the state of Washington from 1981-2010. The data for each was interpolated by PRISM (Parameter-elevation Regressions on Independent Slopes Model), a climate data model that uses algorithms to discover relationships between elevation and precipitation for each grid in a raster dataset. Terrain variations such as slope, coastal proximity, and surface complexity are taken into account, with the results being a digitally created map that's comparable to an expert cartographer interpolating the data by hand, maybe even better, and definitely faster. In the maps below, note the differences in value presentation, with the continuous tone using exact value to denote contour variation and the hypsometric shading separating the data into classes. There are advantages to each, with the most obvious being an easier to interpret legend and dataset in the hypsometric map but more value detail in the continuous tone map. To help with value distinctions in relation to elevation, I chose to add the required contour lines to the continuous tone map. Both maps also employ hillside shading to increase dimensionality for the viewer.