Create Colour Scheme for a Range of Numbers
Given a range of numerical values, this command creates a colour scheme that would be appropriate if the numbers were altitudes (elevation above or below sea level).
beachcolours(range, sealevel = 0, monochrome = FALSE,
ncolours = if (monochrome) 16 else 64,
nbeach = 1)
beachcolourmap(range, ...)range |
Range of numerical values to be mapped. A numeric vector of length 2. |
sealevel |
Value that should be treated as zero.
A single number,
lying between |
monochrome |
Logical. If |
ncolours |
Number of distinct colours to use. |
nbeach |
Number of colours that will be yellow. |
... |
Arguments passed to |
Given a range of numerical values, these commands create a colour scheme that would be appropriate if the numbers were altitudes (elevation above or below sea level).
Numerical values close to zero are portrayed in green (representing the waterline). Negative values are blue (representing water) and positive values are yellow to red (representing land). At least, these are the colours of land and sea in Western Australia. This colour scheme was proposed by Baddeley et al (2005).
The function beachcolours returns these colours
as a character vector, while beachcolourmap
returns a colourmap object.
The argument range should be a numeric vector of
length 2 giving a range of numerical values.
The argument sealevel specifies the height value that will
be treated as zero, and mapped to the colour green.
A vector of ncolours colours will be created,
of which nbeach colours will be green.
The argument monochrome is included
for convenience when preparing publications.
If monochrome=TRUE the colour map will be
a simple grey scale containing ncolours
shades from black to white.
For beachcolours,
a character vector of length ncolours specifying colour values.
For beachcolourmap, a colour map (object of class "colourmap").
Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner r.turner@auckland.ac.nz
Baddeley, A., Turner, R., Moller, J. and Hazelton, M. (2005) Residual analysis for spatial point processes. Journal of the Royal Statistical Society, Series B 67, 617–666.
plot(beachcolourmap(c(-2,2)))
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