plot.symbolmap: Plot a Graphics Symbol Map

Description

Plot a representation of a graphics symbol map, similar to a plot legend.

Usage

# S3 method for symbolmap
plot(x, ..., main, xlim = NULL, ylim = NULL,
                         vertical = FALSE,
                         side = c("bottom", "left", "top", "right"),
                         annotate = TRUE, labelmap = NULL, add = FALSE,
                         nsymbols = NULL, warn = TRUE, colour.only=FALSE)

Value

None.

Arguments

x: Graphics symbol map (object of class "symbolmap").
...: Additional graphics arguments passed to points, symbols or axis.
main: Main title for the plot. A character string.
xlim,ylim: Coordinate limits for the plot. Numeric vectors of length 2.
vertical: Logical. Whether to plot the symbol map in a vertical orientation.
side: Character string specifying the position of the text that annotates the symbols.
annotate: Logical. Whether to annotate the symbols with labels.
labelmap: Transformation of the labels. A function or a scale factor which will be applied to the data values corresponding to the plotted symbols.
add: Logical value indicating whether to add the plot to the current plot (add=TRUE) or to initialise a new plot.
nsymbols: Optional. The maximum number of symbols that should be displayed.
warn: Logical value specifying whether to issue a warning when the plotted symbol map does not represent every possible discrete value.
colour.only: Logical value. If TRUE, the colour map information will be extracted from the symbol map, and only this colour map will be plotted. If FALSE (the default) the entire symbol map is plotted, including information about symbol shape and size as well as colour.

Author

Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner rolfturner@posteo.net and Ege Rubak rubak@math.aau.dk.

Details

A graphics symbol map (object of class "symbolmap") is an association between data values and graphical symbols.

This command plots the graphics symbol map itself, in the style of a plot legend.

For a map of continuous values (a symbol map which represents a range of numerical values) the plot will select about nsymbols different values within this range, and plot their graphical representations.

For a map of discrete inputs (a symbol map which represents a finite set of elements, such as categorical values) the plot will try to display the graphical representation of every possible input, up to a maximum of nsymbols items. If there are more than nsymbols possible inputs, a warning will be issued (if warn=TRUE, the default).

Examples

Run this code

  g <- symbolmap(inputs=letters[1:10], pch=11:20)
  plot(g)

  g2 <- symbolmap(range=c(-1,1),
                    shape=function(x) ifelse(x > 0, "circles", "squares"),
                    size=function(x) sqrt(ifelse(x > 0, x/pi, -x)),
                    bg = function(x) ifelse(abs(x) < 1, "red", "black"))
  plot(g2, vertical=TRUE, side="left", col.axis="blue", cex.axis=2)

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