Imagine a traditional geographic map where Texas looks like Texas and Delaware looks like Delaware. No matter how dark you shade in the tiny states like Delaware, they’ll always be dwarfed by larger states like Texas. Then how can we read the information more effectively?
The go to answer in those specific situations is Tile Grid Map.
When would you use Tile Grid Map?
A tile grid map can be a clear way to show ranges of values for a country or a selection of countries without representing the exact geography of each area. This can be useful for creating a simple and clear visualization of values that would not be otherwise easily seen for areas that have a small geography. This is particularly true when creating a choropleth map of the entire United States. Large states like Alaska, California, and Texas can be easily seen but determining the value of smaller areas like Rhode Island are difficult when viewed at the scale of the entire United States. A tile grid map, by sizing each geographic unit uniformly, makes it easy to interpret the values for all states.
Example:
Here is my example of Tile Grid Chart where I have taken a sample data and build a YOY profit chart upon it. As you see in the Viz, I am comparing 2017 vs 2018 and showing the profit margin.
Also added arrows to show where it is increased, decreased or haven’t changed over the selected period.
So What Are the Pitfalls of Tile Grid Maps?
The biggest issue with any variant of the tile grid maps above is that they are not accurate maps. If you can’t handle seeing DC adjacent to both NC and DE, or any other of a number of odd re-neighborings, they aren’t for you. I would argue in many cases this is not the right tradeoff to make, but it is not an unreasonable one.
In some cases, it won’t be a matter of preference. Sometimes the size and shape of states matters for the data. Consider a map showing where a disease had been reported. If it is all in the northeast, that gives a sense of where it is and where resources are needed. The fact that it is in ten states is less important than that it is still a ways away from most of the U.S. In short, if counting isn’t the point, and geography matters, a choropleth may be better.
Use Cases:
For more innovative ideas , I found http://datavizcatalogue.com/blog/chart-combinations-tile-grid-maps/ this post by Severino Ribecca which takes us to our next level of imagination and shows how we can show Tile Grid Maps more appealing by combining different charts.
You can find my Tableau example here, https://public.tableau.com/profile/navyasree.potluri5017#!/vizhome/TileGripMap/TileGridMap
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