Prepare Your Readers

Your job as a data designer is to communicate what you know to your audience. They most likely didn’t look at the data, so they might not see the same thing that you see if there’s no explanation or setup. My rule of thumb is to assume that people are showing up to my graphics blindly, and with sharing via Facebook and Twitter and links from other blogs, that’s not all that far off.

For example, Figure 9-2 shows a screenshot of an animated map I made. If you haven’t seen this graphic before, you probably have no clue what you’re looking at. Given the examples in Chapter 8, “Visualizing Spatial Relationships,” your best guess might be openings for some store.

Figure 9-2: Map without a title or context


Watch the full map animation at

The map actually shows geotagged tweets that were posted around the world during the inauguration of President Barack Obama on Tuesday, January 20, 2009, at noon Eastern Standard Time. The animation starts early Monday morning, and as the day moves on, more people wake and tweet at a steady rate. The number of tweets per hour increases as the event nears, and Europe gets in on some of the action as the United States sleeps. Then Tuesday morning starts, and then boom—there’s huge excitement as the event actually happens. You can easily see this progression in Figure 9-3. Had I provided this context for Figure ...

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