Smooth colour gradient between n colours

Usage

scale_colour_gradientn(..., colours, values = NULL, space = "Lab", na.value = "grey50", 
  guide = "colourbar")

scale_fill_gradientn(..., colours, values = NULL, space = "Lab", na.value = "grey50", 
      guide = "colourbar")

scale_color_gradientn(..., colours, values = NULL, space = "Lab", na.value = "grey50", 
      guide = "colourbar")

Arguments

guide
Type of legend. Use "colourbar" for continuous colour bar, or "legend" for discrete colour legend.
colours
vector of colours
values
if colours should not be evenly positioned along the gradient this vector gives the position (between 0 and 1) for each colour in the colours vector. See rescale for a convience function to map an arbitrary range to between 0 and 1.
space
colour space in which to calculate gradient. "Lab" usually best unless gradient goes through white.
...
Other arguments passed on to discrete_scale to control name, limits, breaks, labels and so forth.
na.value
Colour to use for missing values

Description

Smooth colour gradient between n colours

Examples

# scale_colour_gradient make it easy to use existing colour palettes dsub <- subset(diamonds, x > 5 & x < 6 & y > 5 & y < 6) dsub$diff <- with(dsub, sqrt(abs(x-y))* sign(x-y)) (d <- qplot(x, y, data=dsub, colour=diff))

d + scale_colour_gradientn(colours = rainbow(7))

breaks <- c(-0.5, 0, 0.5) d + scale_colour_gradientn(colours = rainbow(7), breaks = breaks, labels = format(breaks))

d + scale_colour_gradientn(colours = topo.colors(10))

d + scale_colour_gradientn(colours = terrain.colors(10))

# You can force them to be symmetric by supplying a vector of # values, and turning rescaling off max_val <- max(abs(dsub$diff)) values <- seq(-max_val, max_val, length = 11) d + scale_colour_gradientn(colours = topo.colors(10), values = values, rescaler = function(x, ...) x, oob = identity)

d + scale_colour_gradientn(colours = terrain.colors(10), values = values, rescaler = function(x, ...) x, oob = identity)