Hi Students,

I will start with… a map!

The map above shows the distribution of slavery in the south, and it’s been making its way around the web. I love this map for a number of different reasons, and if you’re a data nerd you probably do too. First, it’s an old thing that resembles lots of new things. Maps partitioned by logical boundaries and colored according to some sort of metric are a standard communication mechanism. You can’t wander the blogosphere for 10 minutes without tripping over a color-coded map trying to convey some moderately interesting result. For example, this collection of maps explains why all my female friends are named Jennifer, and why all your friends are named Jessica or Ashely or Jessica Ashley. Keep these maps handy; you can use them to wow a friend at your next dinner party.

Second, Abe Lincoln loved this map, and people love Lincoln (at least I do). And why wouldn’t they, there are so many great things about Abe. We all know he saved the union, freed the slaves, and fought vampires. But did you know that he was freakishly strong? According to one biographer, “he could not only lift from the ground enormous weight, but could throw a cannonball or a maul farther than anyone in New Salem.” That’s impressive. Oh, he was also the president… did I mention that?

Finally, we love this map for the same reason that Lincoln did. It tells a compelling story, a story hard to understand without visualization. It shows that slavery in the Confederacy was not homogenous, the density of slavery varied. Gareth Cook explains the importance of the map in his article for The New Yorker:

In the map, Lincoln saw testimony that the American south was not a uniform bloc. Areas of heavy slavery—the darkened banks along the Mississippi River, for example—tended to be secessionist, but the areas in between held the hope of pro-Union sympathy. Unlike traditional cartography, the map was designed to portray political terrain and, in Lincoln’s mind, moral terrain. The President called it his “slave map.” Today we would call it an infographic.

Infographics tell stories. They told Lincoln that there might be a wedge that he could exploit to win over the hearts and minds of the Confederacy. They tell expectant mothers to avoid the name Sophia. They allow us better understand the human toll of the war in Afghanistan. They deconstruct complex information into smaller pieces that we can reason about.

Visualizations, in general, are effective because they engage our visual processing system. Visual information is easier to process and easier to remember than text and tables. It makes me think that maybe xkcd is right. In the future, all information will be conveyed through infographics.

What does that mean? How is it actionable? Well, before you start creating an infographic you should think about the story you are trying to tell. This seems fairly obvious and in line with standard design thinking, but many people screw this up. They break out Photoshop or d3 before they understand their narrative.

How do you construct an effective narrative? Alberto Cairo has an excellent book on creating infographics called The Functional Art. This article provides a summary of his suggestions. At a high level his advice is: “structure first, then style.” Think about the story you are trying to tell first, then try to figure out how to visually convey that story. Thinking about the story may involve sketching candidate presentations on paper and working through the layout. If you understand the structure and narrative of your story, your final product will likely be easier to create and will better convey your message.