Visualizing Spatial Relationships - Data Points: Visualization That Means Something - page 294

Open your brand spanking new choropleth map in Illustrator or a modern
browser such as Firefox, Safari, or Chrome to see the fruits of your labor,
as shown in Figure 8-18. It's easy to see now where in the country there
were higher unemployment rates during August 2010. Obviously a lot of
the west coast and much of the southeast had higher rates, as did Alaska
and Michigan. There are a lot of counties in middle America with relatively
lower unemployment rates.
With the hard part of this exercise done, you can customize your map to
your heart's content. You can edit the SVG file in Illustrator, change border
colors and sizes, and add annotation to make it a complete graphic for a
larger audience. (Hint: It still needs a legend.)
FIGurE 8-18 Choropleth map showing unemployment rates
The best part is that the code is reusable, and you can apply it to other
datasets that use the FIPS code. Or even with this same dataset, you can
mess around with color scheme to design a map that fits with the theme of
your data.
Depending on your data, you can also change the thresholds for how to color
each region. The examples so far used equal thresholds where regions