Designing for an Audience - Data Points: Visualization That Means Something - page 601

As the tour guide of data, you assume similar responsibilities. It's your job to
point out the direction of interest, provide background, make sure you don't
confuse, and keep focus. The extent that you provide these to readers varies
by who your readers are, but above all else, you must show the truth.

DATA BACKGROUND

Remember my wedding photos in Chapter 1? At first it was foreign—a picture
plucked out of context—but as I told you more, it felt real, and you had a better
sense of what happened that day. Apply this more generally to visualization,
and it's easier for people to understand the data. Show people a graph out
of context, and it's more difficult to interpret.

For example, look at Figure 6-17. This is a map from the live flight tracking
site FlightAware. From the flight information page, I can tell you this was
flight N48DL on April 19, 2012, from Slidell, Louisiana to Sarasota, Florida. The
duration of the flight was 4 hours and 23 minutes.

Other than what looks like a broken flight tracker, there doesn't seem to be
anything notable about this map. However, the full story is that this is the flight
path of a small plane that circled over the Gulf of Mexico for more than 2 hours
and eventually sank in the ocean. The pilot was unresponsive. Suddenly, the
map means something else.

Note: The best way to learn where people
are is to show your work to those who don't
know your data. You get an immediate sense of
understanding just from first impressions.

Sometimes, when you work with a dataset for a while, it's
easy to forget that others aren't as familiar with it as you are.
When you know all the intimate details, it's hard to step back
and remember what it was like when you first opened up a
file or database—just a bunch of numbers. However, that's
where a lot of people are when they look at a visualization,
so bring them up to speed.

GUIDANCE FOR CONCEPTS

This is mentioned in the previous chapter, but it's worth another look, more
broadly speaking. Statistical graphics used for data exploration and designed
by statisticians can be great tools and are the foundation of plenty of fine
graphics. The challenge with a general audience though is that you have to
put yourself in the place of those who don't work with data for a living. It's
not enough to simply expect people to know what you do.