A diverging color palette represents continuous data that varies around a meaningful midpoint. It uses contrasting hues for the low and high ends, with a lighter, generally desaturated hue at the midpoint. section 4.3.1
Use one when the extremes matter as much as their direction from the midpoint:
- Show temperatures above and below an average. section 4.3.1
- Compare revenue against a target. section 4.3.1
- Display political balance or income above and below the poverty line. section 4.3.1
A sequential palette can show larger values, but a diverging palette makes both extremes easier to see by emphasizing their opposition. Choose the midpoint carefully: without a meaningful center, the two-sided treatment can mislead. Also test the result in black and white, where diverging palettes often lose their distinction. section 4.3.1
Figure 4.25 The sequential palette on the left is fine for highlighting the larger values, but the diverging palette on the right makes it easier to see both extremes (the low and the high) for the same data set.
Compare a sequential palette with a diverging palette applied to the same data; the latter makes low and high extremes easier to distinguish. section 4.3.1
