scale-colour-gradientn

Continuous n-stop colour gradient.

Walks colours as a sequence of stops and linearly interpolates between adjacent stops. Useful for ramps that require more than two anchor colours (for example a ColorBrewer palette used as a continuous ramp).

Usage

scale-colour-gradientn(
  colours,
  name,
  limits,
  oob,
  breaks,
  labels,
)

Parameters

Parameter	Default	Description
colours		Array of two or more colours.
name		Legend title. Overrides any name set via labels when both are present.
limits		Pair (lo, hi) clipping the trained domain, or none.
oob		Out-of-range policy: "drop" (default) removes rows whose value falls outside limits; "squish" clamps continuous values to the nearest endpoint.
breaks		Array of break values for the legend, or auto.
labels		Array of legend labels aligned with breaks, or auto.

Returns

Scale object consumed by plot.

Examples

Three-stop ramp interpolating green-yellow-red across the domain.

#let d = range(0, 12).map(i => (x: i, y: i, z: i * 0.5))
#plot(
  data: d,
  mapping: aes(x: "x", y: "y", colour: "z"),
  layers: (geom-point(size: 3pt),),
  scales: (scale-colour-gradientn(colours: (
    rgb("#1a9850"), rgb("#ffffbf"), rgb("#d73027"),
  )),),
  width: 10cm,
  height: 6cm,
)

Feeding a brewer palette into scale-colour-gradientn lifts a discrete palette into a continuous ramp.

#let d = range(0, 12).map(i => (x: i, y: i, z: i * 0.5))
#plot(
  data: d,
  mapping: aes(x: "x", y: "y", colour: "z"),
  layers: (geom-point(size: 3pt),),
  scales: (scale-colour-gradientn(
    colours: brewer-palette("RdYlBu"),
  ),),
  width: 10cm,
  height: 6cm,
)

See also

scale-colour-gradient, scale-colour-gradient2, scale-fill-gradientn.