Database Reference
In-Depth Information
ProBlems wITh ChloroPleThs
A
chloropleth
is a heatmap with the shapes of countries or states instead of
blocks. Showing chloropleths using non-normalized numbers, for instance
gross domestic product (GDP) instead of GDP per capita, often gives a
misleading impression, showing a map of the population more than the
figure being chosen. Figure 12-2 shows an example of this from the popular
cartoon XKCD (
http://xkcd.com/1138/
).
F I g u R e 12 -2
XKCD showing the problem with heatmaps
eXPlAInIng PeRSPeCTIVe AnD
PeRCeIVIng CoMPARISonS
How you perceive the difference between two objects is dependent on a
variety of factors—the difficulty with using area as a comparison method is
covered in Chapter 2, and the challenges of using 3D is covered in Chapter
1. Other factors include their relative positioning and ordering—putting two
