Package 'colorRamps'

Builds color maps

Description

This (v2) is a rewrite of the colorRamps package. It now contains two function table.ramp and rgb.tables that allow easy construction of color palettes. This version contains two new palettes similar to the Matlab default palette (matlab.like and matlab.like2).

I built colorRamps because I needed to use a particular palette and got tired of sourcing in my code into every session. Now I can install and forget. Despite using R for years, I had not noticed the alternative colorRamp which may suit your needs. If you want really attractive palettes, get the RColorBrewer package from CRAN. For certain applications the RColorBrewer palettes do not work for me, hence this package.

Details

Package:	colorRamps
Type:	Package
Version:	2.0
Date:	2007-09-09
License:	GPL

Most functions take a single argument n that specifies the number of colors to generate.

Author(s)

Tim Keitt

Maintainer: Tim Keitt <[email protected]>

References

Keitt, T. H. (2008) Coherent ecological dynamics induced by large scale disturbance. Nature 454:331-334

Examples

filled.contour(volcano, col = ygobb(21), asp = 1)

---

Returns a gradient color map

Description

blue2red makes a color map that runs from blue -> cyan -> yellow -> red. blue2green makes a color map that runs from blue -> magenta -> yellow -> green. green2red makes a color map that runs from green -> cyan -> magenta -> red

Usage

blue2red(n)
blue2green(n)
green2red(n)

Arguments

n	number of colors

Details

These are double-ramp maps with a sharp transition from cooler colors to warmer colors at the midpoint. With proper scaling, this will highlight the mean, median, etc.

Value

A colormap

Author(s)

Tim Keitt <[email protected]>

References

Keitt, T. H. (2008) Coherent ecological dynamics induced by large scale disturbance. Nature 454:331-334

See Also

rgb

Examples

image(matrix(1:400, 20), col = blue2red(400))
image(matrix(1:400, 20), col = blue2green(400))
image(matrix(1:400, 20), col = green2red(400))

---

Returns a gradient color map

Description

blue2yellow makes a blue to yellow gradient color map

Usage

blue2yellow(n)
cyan2yellow(n)
magenta2green(n)

Arguments

n	number of colors

Details

These are single gradient maps that smoothly transition from cooler to warmer colors. See blue2red for double gradient maps.

Value

A color map

Author(s)

Tim Keitt <[email protected]>

References

Keitt, T. H. (2008) Coherent ecological dynamics induced by large scale disturbance. Nature 454:331-334

See Also

rgb

Examples

image(matrix(1:400, 20), col = blue2yellow(400))

---

Generate color palettes similar to the matlab default

Description

Generates matlab-like color palettes

Usage

matlab.like(n)
matlab.like2(n)
blue2green2red(n)

Arguments

n	number of colors

Details

blue2green2red is simply an alias for matlab.like2.

Value

a color palette

Author(s)

Timothy H. Keitt

References

Keitt, T. H. (2008) Coherent ecological dynamics induced by large scale disturbance. Nature 454:331-334

Examples

image(matrix(1:400, 20), col = blue2yellow(400))

---

generates expanded sets of primary colors

Description

Combines red, green and blue values to create primary colors

Usage

primary.colors(n, steps = 3, no.white = TRUE)

Arguments

n	number of colors to generate (optional)
steps	number of rgb intensity levels
no.white	boolean indicating whether to return white

Details

The standard R palette only provides 8 colors after which colors are recycled. If you need a few more colors that are redily distinguished in multivariate plots, this function can help.

Value

An R color palette

Author(s)

Timothy H. Keitt

References

Keitt, T. H. (2008) Coherent ecological dynamics induced by large scale disturbance. Nature 454:331-334

Examples

x <- matrix(rnorm(100), 10)
x <- sapply(1:10, function(i, x) cumsum(x[,i]), x=x)
par(mfrow = c(1, 2))
matplot(1:10, x, type = 'l', lty = 1, lwd = 3)
matplot(1:10, x, type = 'l', lty = 1, lwd = 3, col = primary.colors(10))

---

constructs color palettes with sharp breaks

Description

rgb.tables wraps table.ramp and simply passes values supplied in the red, green and blue arguments. table.ramp makes a color ramp with a flat top.

Usage

rgb.tables(n, red = c(0.75, 0.25, 1), green = c(0.5, 0.25, 1), blue =
c(0.25, 0.25, 1))
table.ramp(n, mid = 0.5, sill = 0.5, base = 1, height = 1)

Arguments

n	number of colors to generate
red	a length 3 vector with values mid, sill and base
green	same as red
blue	same as red
mid	table center on (0, 1)
sill	width of table top on (0, 1)
base	width of table base on (0, 1)
height	sill height on (0, 1)

Value

rgb.tables returns a color palette. table.ramp returns a simple vector of values.

Author(s)

Timothy H. Keitt

References

Keitt, T. H. (2008) Coherent ecological dynamics induced by large scale disturbance. Nature 454:331-334

See Also

colorRamp

Examples

table.ramp(10)
rgb.tables(10)

---

Returns a gradient color map

Description

ygobb makes a color map that runs from yellow -> green -> olive -> blue -> black.

Usage

ygobb(n)

Arguments

n	number of colors

Details

I am still working on this one.

Value

A colormap

Author(s)

Tim Keitt <[email protected]>

References

Keitt, T. H. (2008) Coherent ecological dynamics induced by large scale disturbance. Nature 454:331-334

See Also

rgb

Examples

image(matrix(1:400, 20), col = ygobb(400))

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