When considering the options available to visualize geographic data, maps are by far the most common and intuitive choice. They are great at helping us understand patterns, trends, and distribution.
There are so many questions that one can answer using maps. For example:
- Which US state has the oldest population?
- What areas in Chicago have the highest obesity rate?
- What country has the highest GDP?
In my case, I was looking to visualize the number of days since the COVID-19 shelter in place order by state.
At first, I tried to create a filled map in Tableau (below). The goal was to understand variations by state, as well as potential outliers.
After creating the map above, I asked myself:
- Can I easily detect the difference between Maine and Vermont, for example?
Answer: No
- Can I look at Puerto Rico or Hawaii and immediately understand how they compare to mainland states?
Answer: No
- Can I accurately determine the outliers in this visualization?
Answer: No
These three negative answers made me immediately conclude that this visualization is not the most effective choice. It is cluttered and does not provide clear answers to my questions.
After considering other map options, such as point distribution and symbol maps, I landed on a choice that seemed more promising: HEX TILE MAP.
A hex tile map assigns identical proportions to all states, which makes comparisons easier as each state becomes clearly visible.
After creating the hex tile map above, I went back to my original questions. This time, my answers were different.
- Can I easily detect the difference between Maine and Vermont, for example?
Answer: Yes
- Can I look at Puerto Rico or Hawaii and immediately understand how they compare to mainland states?
Answer: Yes
- Can I accurately determine the outliers in this visualization?
Answer: Yes
The tile map proved to be a more effective choice for the goal that I had in mind. It was not cluttered, and I was able to clearly determine variations by state, as well as outliers.
Broadly speaking, a few key lessons emerged:
- Don’t stick to your first data visualization choice just because it is in your comfort zone.
- Before creating a chart, make sure that your goal, as well as the questions that you are trying to answer are clearly defined.
- Always have fun trying new things!
If you’re interested to learn how to create a tile map, here’s a useful tutorial.
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