Designing with a Purpose - Data Points: Visualization That Means Something - page 330

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.

P Watch the full
map animation at
http://datafl
.ws/19n .

FIGurE 9-2 Map without a title or context

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 progres-
sion in Figure 9-3. Had I provided this context for Figure 9-2, it probably
would've made a lot more sense.