Understanding Data - Data Points: Visualization That Means Something - page 348

With a time series layout, you can see the high points of the wedding, when our
photographers snapped more shots, and the lulls, when only a few photos were
taken. The peaks in the chart, of course, occur when there is something to take
pictures of, such as when I first saw my wife in her dress or when the ceremony
began. After the ceremony, we took the usual group photos with friends and
family, so there was another spike at that point. Then there was food, and activ-
ity died down, especially when the photographers took a break a little before 4
o'clock. Things picked up again with typical wedding fanfare, and the day came
to an end around 7 in the evening. My wife and I rode off into the sunset.
In the grid layout, you might not see this pattern because of the linear presen-
tation. Everything seems to happen with equal spacing, when actually most
pictures were taken during the exciting parts. You also get a sense of the colors
in the wedding at a glance: black for the suits, white for the wedding dress,
coral for the flowers and bridesmaids, and green for the trees surrounding
the outdoor wedding and reception. Do you get the detail that you would
from the actual photos? No. But sometimes that level isn't necessary at first.
Sometimes you need to see the overall patterns before you zoom in on the
details. Sometimes, you don't know that a single data point is worth a look
until you see everything else and how it relates to the population.
You don't need to stop here, though. Zoom out another level to focus only on
the picture-taking volumes, and disregard the colors and individual photos,
as shown in Figure 1-4.
You've probably seen this layout before. It's a bar chart that shows the same
highs and lows as in Figure 1-3, but it has a different feel and provides a
different message. The simple bar chart emphasizes picture-taking volumes
over time via 15-minute windows, whereas Figure 1-3 still carries some of the
photo album's sentiment.
The main thing to note is that all four of these views show the same data, or
rather, they all represent my wedding day. Each graphic just represents the
day differently, focusing on various facets of the wedding. Interpretation of
the data changes based on the visual form it takes on. With traditional data,
you typically examine and explore from the bar chart side of the spectrum,
but that doesn't mean you have to lose the sentiment of the individual data
point—that single photo. Sometimes that means adding meaningful annotation
that enables readers to interpret the data better, and other times the message
in the numbers is clear, gleaned from the visualization itself.