R: openair colours

openColours {openair} | R Documentation

## openair colours

### Description

Pre-defined openair colours and definition of user-defined colours

### Usage

    openColours(scheme = "default", n = 100)

### Arguments

`scheme` | The pre-defined schemes are "increment", "default", "brewer1", "heat", "jet", "hue", "greyscale", or a vector of R colour names e.g. c("green", "blue"). It is also possible to supply colour schemes from the `RColorBrewer` package. This package defines three types of colour schemes: sequential, diverging or qualitative. See https://colorbrewer2.org/ for more details concerning the orginal work on which this is based. Simplified versions of the `viridis` colours are also available. These include "viridis", "plasma", "magma", "inferno" and "cividis". Sequential colours are useful for ordered data where there is a need to show a difference between low and high values with colours going from light to dark. The pre-defined colours that can be supplied are: "Blues", "BuGn", "BuPu", "GnBu", "Greens", "Greys", "Oranges", "OrRd", "PuBu", "PuBuGn", "PuRd", "Purples", "RdPu", "Reds", "YlGn", "YlGnBu", "YlOrBr", "YlOrRd". Diverging palettes put equal emphasis on mid-range critical values and extremes at both ends of the data range. Pre-defined values are: "BrBG", "PiYG", "PRGn", "PuOr", "RdBu", "RdGy", "RdYlBu", "RdYlGn", "Spectral". Qualitative palettes are useful for differentiating between categorical data types. The pre-defined schemes are "Accent", "Dark2", "Paired", "Pastel1", "Pastel2", "Set1", "Set2", "Set3". A colorblind safe pallette "cbPalette" is available based on the work of: http://jfly.iam.u-tokyo.ac.jp/color/ Note that because of the way these schemes have been developed they only exist over certain number of colour gradations (typically 3–10) — see ?`brewer.pal` for actual details. If less than or more than the required number of colours is supplied then `openair` will interpolate the colours.
`n` | number of colours required.

### Details

This in primarily an internal openair function to make it easy for users to select particular colour schemes, or define their own range of colours of a user-defined length.

Each of the pre-defined schemes have merits and their use will depend on a particular situation. For showing incrementing concentrations e.g. high concentrations emphasised, then "default", "heat", "jet" and "increment" are very useful. See also the description of `RColorBrewer` schemes for the option `scheme`.

To colour-code categorical-type problems e.g. colours for different pollutants, "hue" and "brewer1" are useful.

When publishing in black and white, "greyscale" is often convenient. With most openair functions, as well as generating a greyscale colour gradient, it also resets strip background and other coloured text and lines to greyscale values.

Failing that, the user can define their own schemes based on R colour names. To see the full list of names, type `colors()` into R.

### Value

Returns colour values - see examples below.

### Author(s)

David Carslaw

### References

https://colorbrewer2.org/

### Examples

    # to return 5 colours from the "jet" scheme:
    cols <- openColours("jet", 5)
    cols

    # to interpolate between named colours e.g. 10 colours from yellow to
    #  green to red:
    cols <- openColours(c("yellow", "green", "red"), 10)
    cols

[Package openair version 2.8-5 Index]