How big is that, though?

This is Hans, a software engineer at Datawrapper and the person who works a lot on the locator map feature. For this week’s edition of the Weekly Chart, I will talk about area sizes and how to display them.

Even though I work with maps all the time, it’s hard for me to grasp the size of an area if its bigger than my flat. For example, when reading in the news about a 2400 km² locus swarm that is devastating Kenya, I wondered: How big is that? I wanted to find out, so I first built a tool (scroll down to learn more) and then a map that compares 2400 km² with the size of London:

A classical way to explain unimaginable areas is to compare them to more familiar areas such as “so and so many football fields” (well, at least in countries where football is popular) or, if you live in Germany, “so and so many Saarlands” (a small German Federal State).

A technique that appeals more to me as a map maker is to show the area on a map the viewer is familiar with.

Since this is a common use case, I decided to create a small, easy-to-use tool that lets you do just that. You can find it on my website. Type in a size and it will generate a circle or square that you can move to the location that is familiar to you and/or your audience. You can then download the shape as a GeoJSON and import it to a map tool like our locator maps.

That’s what I did to create the map above. The visual comparison impressed me a lot! I wasn’t aware of how big the swarm was before I made the map.

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That’s it for this week! Head to our Academy to learn more about creating locator maps and importing GeoJSONs. Or click on “Edit this chart” in the top right corner of the visualization to open an editable copy in Datawrapper. We’ll see you next week!