Define cols options for openair plots

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)

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

Arguments

scheme

Any one of the pre-defined openair schemes (e.g., "increment") or a user-defined palette (e.g., c("red", "orange", "gold")). See openColours() 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.

Value

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

Examples

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