Database Reference
In-Depth Information
Figure 10-17. Two solutions to the missing values problem: orange-blue (left) and a dark map
(right)
WARNING
One further consideration when choosing a color scheme is whether the viewer of the
visualization will be able to view it in color, or will see it only in grayscale. If there's any
chance the viewer will see a grayscale version, steer clear of diverging color palettes and
stick with sequential.
The two versions of the map are shown in grayscale in
Figure 10-18
. Notice how it's impos-
sible to tell the difference between the dark of very high values (like in Scandinavia) and the
dark of very low values (like in Africa) when viewing the diverging color palette in gray-
scale. With sequential, higher values are always darker than lower values, so it's perfectly
clear in grayscale. If there's any chance your viewer won't have a color display, use sequen-
tial.
