R: HCL-Based Discrete Sequential Color Scales for ggplot2

scale_colour_discrete_sequential {colorspace} | R Documentation

## HCL-Based Discrete Sequential Color Scales for ggplot2

### Description

Discrete ggplot2 color scales using the color palettes generated by `sequential_hcl`.

### Usage

    scale_colour_discrete_sequential(
      palette = NULL,
      c1 = NULL,
      c2 = NULL,
      cmax = NULL,
      l1 = NULL,
      l2 = NULL,
      h1 = NULL,
      h2 = NULL,
      p1 = NULL,
      p2 = NULL,
      alpha = 1,
      rev = TRUE,
      nmax = NULL,
      order = NULL,
      aesthetics = "colour",
      ...
    )

    scale_color_discrete_sequential(
      palette = NULL,
      c1 = NULL,
      c2 = NULL,
      cmax = NULL,
      l1 = NULL,
      l2 = NULL,
      h1 = NULL,
      h2 = NULL,
      p1 = NULL,
      p2 = NULL,
      alpha = 1,
      rev = TRUE,
      nmax = NULL,
      order = NULL,
      aesthetics = "colour",
      ...
    )

    scale_fill_discrete_sequential(..., aesthetics = "fill")

### Arguments

`palette` | The name of the palette to be used. Run `hcl_palettes(type = "sequential")` for available options.
`c1` | Beginning chroma value.
`c2` | Ending chroma value.
`cmax` | Maximum chroma value.
`l1` | Beginning luminance value.
`l2` | Ending luminance value.
`h1` | Beginning hue value.
`h2` | Ending hue value. If set to `NA`, generates a single-hue scale.
`p1` | Control parameter determining how chroma should vary (1 = linear, 2 = quadratic, etc.).
`p2` | Control parameter determining how luminance should vary (1 = linear, 2 = quadratic, etc.).
`alpha` | Numeric vector of values in the range `[0, 1]` for alpha transparency channel (0 means transparent and 1 means opaque).
`rev` | If `TRUE` (default), reverses the order of the colors in the color scale (compared to `sequential_hcl`).
`nmax` | Maximum number of different colors the palette should contain. If not provided, is calculated automatically from the data.
`order` | Numeric vector listing the order in which the colors should be used. Default is `1:nmax`.
`aesthetics` | The ggplot2 aesthetics to which this scale should be applied.
`...` | common discrete scale parameters: `name`, `breaks`, `labels`, `na.value`, `limits` and `guide`. See `discrete_scale` for more details.

### Details

If both a valid palette name and palette parameters are provided then the provided palette parameters overwrite the parameters in the named palette. This enables easy customization of named palettes.

Compared to `sequential_hcl` the ordering of the colors in the sequential ggplot2 scale are reversed by default (i.e., `rev = TRUE`) to be more consistent with ggplot2's own scales such as `scale_color_brewer`. For most named palettes this leads to darker and more colorful colors for larger values on the scale. This is typically the better default on light/white backgrounds.

### Examples

    library("ggplot2")

    # default colors
    ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)) +
      geom_point() + scale_color_discrete_sequential() + theme_classic()

    # customization of named palette
    ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)) +
      geom_point() + scale_colour_discrete_sequential(palette = "Reds", nmax = 4, p2 = 1.5) +
      theme_classic()

    # color scale "Terrain"
    ggplot(iris, aes(Sepal.Length, fill = Species)) +
      geom_density(alpha = 0.7) + scale_fill_discrete_sequential(palette = "Terrain") + theme_minimal()

[Package colorspace version 2.0-1 Index]