breakColors
Color palette for (symmetric) breaks
Given a vector of breaks specifying a set of intervals, this function provides a vector of colors for the indicating the intervals graphically. If the intervals are arranged symmetrically around a specified value, the colors try to reflect this.
 Keywords
 utilities
Usage
breakColors(breaks, colors, center = 0, tol = 0.001)
Arguments
 breaks
 a vector of breaks
 colors
 either an explicit vector of colors, or a palette function that takes a number and returns a vector of colors
 center
 optional center around which to check for symmetry
 tol
 tolerance (as relative error) for deviation from mathematically exact symmetry
Details
The meaning of symmetrical is rather generous here: it is enough that the intervals specified by breaks
are of equal length and that center
is one of the breaks. This means we allow for more or less intervals on one side of center
.
This really only works well if colors
is specified as g2r.colors
, which returns a symmetrical color vector (from green to red) if an even number of colors is requested. The whole point is then that if there are more classes to one side of center
than to the other, this will be reflected by deeper shades of red or green on the appropriate side.
Value

A vector of colors, of length one less than the number of breaks.
See Also
Examples
## Fully symmetrical breaks
br1 = (3) : 3
co1 = breakColors(br1, g2r.colors)
co1
doLegend(br1, co1, 1)
## Truncated on one side
br2 = (2) : 4
co2 = breakColors(br2, g2r.colors)
co2
doLegend(br2, co2, 1)
## Does not work with other color schemes
co3 = breakColors(br2, heat.colors)
co3
doLegend(br2, co3, 1)