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 `range[1]`

and `range[2]`

.

monochrome

Logical. If `TRUE`

then a greyscale colour map is
constructed.

ncolours

Number of distinct colours to use.

nbeach

Number of colours that will be yellow.

…

Arguments passed to `beachcolours`

.

For `beachcolours`

,
a character vector of length `ncolours`

specifying colour values.
For `beachcolourmap`

, a colour map (object of class `"colourmap"`

).

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.

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.

# NOT RUN { plot(beachcolourmap(c(-2,2))) # }