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

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)

See also