Color Ramp

Provides a color scheme that map a numeric vector to colors.

Usage

ramp(palette, ...)

Arguments

palette

A character string giving the name of the palette to be used (see color()).

...

Further arguments to be passed to color().

Value

A palette function with argument a vector of values that are mapped to colors. The data midpoint can be specified with an additional midpoint

argument (see examples).

See also

Other color palettes: colour(), info(), scale_picker

Author

N. Frerebeau

Examples

## Visualize a simple DEM model
## Distribution of elevation values
elevation <- hist(volcano)


## Where are breaks?
elevation$breaks
#>  [1]  90 100 110 120 130 140 150 160 170 180 190 200

## Build palette function
ramp_BuRd <- ramp(palette = "BuRd")

(col <- ramp_BuRd(elevation$breaks))
#>  [1] "#2166AC" "#3986BC" "#66A9CF" "#9CCAE1" "#CAE1EE" "#E8F0F4" "#F9ECE4"
#>  [8] "#FCD5C0" "#F5AE8D" "#E37E64" "#CC4C43" "#B2182B"
#> attr(,"breaks")
#>  [1]  90 100 110 120 130 140 150 160 170 180 190 200
image(volcano, col = col)
legend("topright", legend = attr(col, "breaks"), fill = col)


## Rescale to midpoint
(col <- ramp_BuRd(elevation$breaks, midpoint = 160))
#>  [1] "#2166AC" "#347FB9" "#4D99C6" "#7AB6D5" "#A3CDE2" "#C7DFED" "#E0ECF2"
#>  [8] "#F7F7F7" "#FAE6DA" "#FBD2BC" "#F6B495" "#EB9072"
#> attr(,"breaks")
#>  [1]  90 100 110 120 130 140 150 160 170 180 190 200
image(volcano, col = col)
legend("topright", legend = attr(col, "breaks"), fill = col)