plot.colourmap: Plot a Colour Map

Description

Displays a colour map as a colour ribbon

Usage

## S3 method for class 'colourmap':
plot(x, ...,
       main, xlim = NULL, ylim = NULL, vertical = FALSE, axis = TRUE)

Arguments

Colour map to be plotted. An object of class "colourmap".

...

Graphical arguments passed to image.default.

main

Main title for plot. A character string.

xlim

Optional range of x values for the location of the colour ribbon.

ylim

Optional range of y values for the location of the colour ribbon.

vertical

Logical flag determining whether the colour ribbon is plotted as a horizontal strip (FALSE) or a vertical strip (TRUE).

axis

Logical flag determining whether an axis should be plotted showing the numerical values that are mapped to the colours.

Value

None.

Details

This is the plot method for the class "colourmap". An object of this class (created by the function colourmap) represents a colour map or colour lookup table associating colours with each data value.

The command plot.colourmap displays the colour map as a colour ribbon. This plot can be useful on its own to inspect the colour map.

To annotate an existing plot with an explanatory colour ribbon, specify add=TRUE and use the arguments xlim and/or ylim to control the physical position of the ribbon on the plot.

Examples

Run this code

co <- colourmap(rainbow(100), breaks=seq(-1,1,length=101))
  plot(co)
  plot(co, vertical=TRUE)
  ca <- colourmap(rainbow(8), inputs=letters[1:8])
  plot(ca)