“But whatever the map, all it takes is one. Cartophilia, the love of maps, is a love at first sight. It must be predestined, written somewhere in the chromosomes.”
Ken Jennings - "Maphead"
Have you ever used the Bonne Projection as a Valentine’s Day card? Do you belt out “Wow, a Choropleth Map!” when you see a map of customer sentiment, or perhaps “Happiness” as you see below. If so, you and former Jeopardy conqueror Ken Jennings have something in common.
Map: Courtesy of New York Times
We’re not exactly certain when Mr. Jennings found the time to write a brilliant book about geography. Perhaps sometime in between competing against Watson and perusing old Encyclopedia Britannica’s? But for us “Cartophiles” we are grateful he did.
“Maphead” is an exploration of human interest and passion as much as it is about geography. The book introduces us not only to Jennings early love of all things geography, but also presents us some unique characters for the world of antique map collecting, the National Geographic Spelling Bee as well as Geo-caching. Many of us are united by our love of maps and seeing data represented spatially.
The New York Times online have offered up some really cool thematic and choropleth maps over the past couple of years that we’re sure Ken Jennings has enjoyed. The appeal of the “Pursuit of Happiness” map above is that it results in questions that may never get asked if the data was not presented spatially. What does this map represent? This particular map utilized population data from the 2002 US Economic Census to be used to derive a ratio between population and arts, recreation and entertainment entities. Because the data from this census was converted from census datasets to a choropleth map, the mapmaker utilizes the human brains immense ability to process information visually.
Here are some other great Choropleth and thematic maps from the New York Times:
There is an excellent geography school in the Annapolis Valley in Nova Scotia called COGS (Center of Geographic Sciences). It is there that many budding GIS professionals get to hone their interest and perfect their abilities in ArcGIS, Remote Sensing or Cartography. Two of our professors: Konrad and Ela Dramowicz taught a course in GIS for Business which included a number of hands-on exercises building Choropleth maps. Their article on Chororpleth mapping and exploratory data analysis in Directions Magazine is definitely worth a read.
Data exploration and Choropleth mapping are important to work in concert together. For variables with a more normal distribution, the standard deviation classification is most appropriate as you saw in the happiness map above. Choropleth mapping often uses ratios to eliminate the differences in sizes between different areas on the map.
The article also delves into the use of Kolmogorov-Smirnov test for normality to determine the appropriateness of the standard deviation classification. The authors explore normality further by examining the histograms of two variables: Average Value of Dwelling % and University Degree %
Maps and spatial representation data catch our eyes. They allow us to interact with data in ways spreadsheets and data tables do not. We see patterns, we ask questions, and we want to learn more. That is the power of maps.
Ken Jennings… once again, you have the correct answer.