Gradient colour scales
scale_*_gradient
creates a two colour gradient (low-high),
scale_*_gradient2
creates a diverging colour gradient (low-mid-high),
scale_*_gradientn
creates a n-colour gradient.
scale_colour_gradient( ..., low = "#132B43", high = "#56B1F7", space = "Lab", na.value = "grey50", guide = "colourbar", aesthetics = "colour" ) scale_fill_gradient( ..., low = "#132B43", high = "#56B1F7", space = "Lab", na.value = "grey50", guide = "colourbar", aesthetics = "fill" ) scale_colour_gradient2( ..., low = muted("red"), mid = "white", high = muted("blue"), midpoint = 0, space = "Lab", na.value = "grey50", guide = "colourbar", aesthetics = "colour" ) scale_fill_gradient2( ..., low = muted("red"), mid = "white", high = muted("blue"), midpoint = 0, space = "Lab", na.value = "grey50", guide = "colourbar", aesthetics = "fill" ) scale_colour_gradientn( ..., colours, values = NULL, space = "Lab", na.value = "grey50", guide = "colourbar", aesthetics = "colour", colors ) scale_fill_gradientn( ..., colours, values = NULL, space = "Lab", na.value = "grey50", guide = "colourbar", aesthetics = "fill", colors )
... |
Arguments passed on to
|
low, high |
Colours for low and high ends of the gradient. |
space |
colour space in which to calculate gradient. Must be "Lab" - other values are deprecated. |
na.value |
Colour to use for missing values |
guide |
Type of legend. Use |
aesthetics |
Character string or vector of character strings listing the
name(s) of the aesthetic(s) that this scale works with. This can be useful, for
example, to apply colour settings to the |
mid |
colour for mid point |
midpoint |
The midpoint (in data value) of the diverging scale. Defaults to 0. |
colours, colors |
Vector of colours to use for n-colour gradient. |
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
|
Default colours are generated with munsell and
mnsl(c("2.5PB 2/4", "2.5PB 7/10"))
. Generally, for continuous
colour scales you want to keep hue constant, but vary chroma and
luminance. The munsell package makes this easy to do using the
Munsell colour system.
scales::seq_gradient_pal()
for details on underlying
palette
Other colour scales:
scale_alpha()
,
scale_colour_brewer()
,
scale_colour_grey()
,
scale_colour_hue()
,
scale_colour_steps()
,
scale_colour_viridis_d()
df <- data.frame( x = runif(100), y = runif(100), z1 = rnorm(100), z2 = abs(rnorm(100)) ) df_na <- data.frame( value = seq(1, 20), x = runif(20), y = runif(20), z1 = c(rep(NA, 10), rnorm(10)) ) # Default colour scale colours from light blue to dark blue ggplot(df, aes(x, y)) + geom_point(aes(colour = z2)) # For diverging colour scales use gradient2 ggplot(df, aes(x, y)) + geom_point(aes(colour = z1)) + scale_colour_gradient2() # Use your own colour scale with gradientn ggplot(df, aes(x, y)) + geom_point(aes(colour = z1)) + scale_colour_gradientn(colours = terrain.colors(10)) # Equivalent fill scales do the same job for the fill aesthetic ggplot(faithfuld, aes(waiting, eruptions)) + geom_raster(aes(fill = density)) + scale_fill_gradientn(colours = terrain.colors(10)) # Adjust colour choices with low and high ggplot(df, aes(x, y)) + geom_point(aes(colour = z2)) + scale_colour_gradient(low = "white", high = "black") # Avoid red-green colour contrasts because ~10% of men have difficulty # seeing them # Use `na.value = NA` to hide missing values but keep the original axis range ggplot(df_na, aes(x = value, y)) + geom_bar(aes(fill = z1), stat = "identity") + scale_fill_gradient(low = "yellow", high = "red", na.value = NA) ggplot(df_na, aes(x, y)) + geom_point(aes(colour = z1)) + scale_colour_gradient(low = "yellow", high = "red", na.value = NA)
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