Database Reference
In-Depth Information
Figure 10-12. A filled map of Internet usage rates by country, 2010
Tableau automatically gets rid of the circles and replaces them with country shapes colored
an increasingly darker green in proportion to the Internet adoption rate in each country. In
this type of coloring, termed “Sequential” in Tableau, only one color (or
hue
) is used.
This allows us to communicate rate very effectively, and there is less risk that we'll mislead
viewers about the absolute number of Internet users. We can clearly see that the rate is higher
in North America, Europe, and Australia, somewhat lower in South America and most of
Asia, and dramatically lower in Africa.
But can we easily tell which countries are at the halfway point, with around 50 Internet users
out of 100? That would be a difficult list to come up with using the map as we have designed
it. Let's try a different style of coloring: a diverging scale, in which more than one color is
used.
We'll start with a color palette that evokes the notion of hot versus cold:
Orange-White-Blue
Diverging
. To aid cognition, let's change the defaults so that the deepest blue (cold) corres-
ponds to 0 Internet users out of 100, and the deepest orange (hot) corresponds to exactly 100
Internet users out of 100. Tableau defaulted to 0 and 96, which are the min and max values in
