colourOpts: Define 'cols' options for 'openair' plots

In openair: Tools for the Analysis of Air Pollution Data

Define cols options for openair plots

Description

This function provides a convenient way to set options for customising colours in openair plots. It returns a list of options that can be passed to the cols argument of most functions. All arguments are the same as openColours(), but passing colourOpts() allows each function to set an appropriate n value and overwrite certain options if required. colourOpts() and colorOpts() are synonyms.

Usage

colourOpts(
  scheme = "default",
  alpha = 1,
  begin = 0,
  end = 1,
  direction = 1,
  saturation = 0.5,
  lightness = 0.5
)

colorOpts(
  scheme = "default",
  alpha = 1,
  begin = 0,
  end = 1,
  direction = 1,
  saturation = 0.5,
  lightness = 0.5
)

Arguments

scheme	Any one of the pre-defined openair schemes (e.g., "increment") or a user-defined palette (e.g., c("red", "orange", "gold")). Use openSchemes() for a full list of available schemes.
alpha	The alpha transparency level (between 0 and 1) for the colours. 0 is fully transparent, and 1 is fully opaque.
begin, end	For sequential schemes, the fraction (between 0 and 1) of the colour scheme to use. For example, if begin = 0.2 and end = 0.8, only the middle 60% of the colour scheme will be used. This can be useful for avoiding very light or dark colours at the ends of schemes.
direction	The order of the colours. 1 is the default and gives the normal order. -1 will reverse the order of the colours.
saturation	The saturation of the colours, between 0 (completely desaturated, i.e., grey) and 1 (completely saturated). The default is 0.5, which gives the original saturation of the colours. Values less than 0.5 will make the colours more desaturated (greyer), and values greater than 0.5 will make the colours more saturated (vibrant).
lightness	The lightness of the colours, between 0 (completely black) and 1 (completely white). The default is 0.5, which gives the original lightness of the colours. Values less than 0.5 will make the colours darker, and values greater than 0.5 will make the colours brighter.

Value

A list of options that can be passed to the cols argument of plotting functions like polarPlot().

See Also

Other colour functions: openColours(), openSchemes()

Examples

trendLevel(
  mydata,
  "no2",
  cols = colourOpts("viridis", direction = 1, alpha = 0.5)
)

openair documentation built on May 20, 2026, 5:07 p.m.