Graphics Reference
In-Depth Information
members who like to send fewer, bigger messages (for example, photos),
whereas the left side represents family members who send more textual
messages back and forth.
Positive and Negative Values
For numerical values that diverge from a baseline (such as positive and
negative numbers), a diverging color scale draws attention to the opposite
ends of the scale. As shown in
Figure 5-7
,
the center color is typically close
to the brightness of the background color (for example, yellow or beige for a
white background), and the ends are typically vivid colors (such as red and
greenish-blue, or orange and blue).
Figure 5-7:
Diverging color scales are effective for data where you want to
focus on the values at either extreme, such as the extreme positive and
negative values.
Anyapplicationstrackingchangesinpricesandvalues(suchasinvestments,
CPI, migration, or net trade flows) may use a diverging color scale to
differentiate between positive and negative directions, as well as draw
attention to the magnitude at the extremes.
Figure 5-8
shows diverging color scales for income data by various
occupations (available from
www.census.gov
or
www.bls.gov
). The
diverging color indicates percent change in income over the ten-year period
from 2001 to 2010, with a diverging color scale set at 25 percent (the rate
of inflation over the same period). The darker the color is, the greater the
divergence. Oranges toredsindicate realwagesthathavedecreased overthe
period, and greens indicate real wages that have increased. Gray is used to
indicate no data.
