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Do You Need a Single Map, or Several Maps?

This is an Eval Central archive copy, find the original at depictdatastudio.com.

Here’s a counterintuitive dataviz principle:

Sometimes, it’s easier to understand several small graphs than a single graph.

I was recently working with an organization to visualize which states were using their software programs.

States might use:

  • Software A
  • Software B
  • Or, both software A and B

Before: A Single Multicolor Map

Here’s what their visualization looked like.

They had a single U.S. map with one color for each scenario:

  • one color for states using Software A
  • another color for states using Software B, and
  • another color for States using A and B.

Fairly straightforward, right?

It took us a while to spot patterns, though. Three colors is a lot to understand at once. It’s not impossible, but we had to think about it for a moment.

Multicolor (well, multi-hue) maps take a while to interpret.

Multi-hue maps aren’t colorblind-friendly. Here’s a simulation of what the map would look thanks to https://www.color-blindness.com/coblis-color-blindness-simulator/.  

Multicolor maps aren’t grayscale-friendly, either.

After: Small Multiples Maps with One Color Each

In lieu of a multicolor map, try small multiples!

In the redesign, we created three maps instead of one.

Now, we’re showing a single variable on each map, so the audience can understand it at a glance.

Small multiples binary maps (your dark brand color + light gray) are often faster to read than mutli-hue maps. It’s counterintuitive, I know. We’re asking people to read three maps instead of one. But, three fast maps will beat one slow map any day of the week.

Small multiples binary maps are colorblind-friendly. Everyone can spot the dark brand color vs. the light gray.

Finally, small multiples binary maps are grayscale-friendly. Everyone can distinguish the dark gray vs. light gray.

Side-by-Side Comparison

Both styles fit on a single page (a goal in their project).

Both styles have room for explanatory sentences (something I recommend in all one-pagers).

Only the small multiples version is colorblind-friendly and grayscale-friendly. I’d argue that the small multiples version is faster to read, too.

Download the Files

Want to explore my Excel file and Word doc?

You’ll see:

  • How I formatted the Excel table that feeds into the maps
  • How I arranged everything inside good ol’ Word

Download them here: https://depictdatastudio.gumroad.com/l/SmallMultiplesMapsInExcel

Your Turn

Have you split your multicolor map into small multiples?! Get in touch when you apply this technique to your own projects.

October 17, 2022 by Ann K. Emery

Filed Under: depictdatastudio

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