plot.symbolmap: Plot a Graphics Symbol Map

In spatstat/spatstat.geom: Geometrical Functionality of the 'spatstat' Family

Plot a Graphics Symbol Map

Description

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

Usage

## S3 method for class '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,
                         representatives=NULL)

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. Alternatively one of the integers 1 to 4.
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. Ignored if representatives are given.
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.
representatives	Optional. Vector containing the values of the input data which should be shown on the plot.

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).

Value

None.

Nonlinear transformation

For a map of continuous values, if representatives is not specified, then the default is to choose approximately nsymbols values equally spaced within the numerical range.

However, if the symbol map includes a nonlinear transformation (arguments compress and decompress were passed to symbolmap) or if one of its graphical parameters is a colour map which includes a nonlinear transformation (arguments compress and decompress were passed to colourmap) then the representative values will be equally spaced on the compressed scale.

Author(s)

\spatstatAuthors

.

See Also

symbolmap to create a symbol map.

invoke.symbolmap to apply the symbol map to some data and plot the resulting symbols.

Examples

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

  ## squares and circles with area proportional to |x|
  ## For 'squares', size is side length; size = sqrt(area)
  ## For 'circles', size is diameter;    size = sqrt(area * 4/pi)
  g2 <- symbolmap(range=c(-1,1),
                  shape=function(x) ifelse(x > 0, "circles", "squares"),
                  size=function(x) ifelse(x > 0,
                                          sqrt(abs(x)*4/pi),
                                          sqrt(abs(x))),
                  bg = function(x) ifelse(abs(x) < 1, "red", "black"))
  plot(g2, vertical=TRUE, side="left", col.axis="blue", cex.axis=2)
  plot(g2, representatives=c(-1,0,1))

  ## logarithmic display scale
  gl <- symbolmap(range=c(1,1000), pch=21,
                  bg=function(x) ifelse(x < 50, "red", "blue"),
                  cex=function(x) ifelse(x < 100, 1, 2),
                  compress=log10)
  gl(10)
  plot(gl, nsymbols=4)

  ## logarithmic symbol map
  gll <- symbolmap(range=c(1,1000),
                   transform=log10, size=function(x) { 1 + x },
                   compress=log10)
  gll(10)
  plot(gll, nsymbols=4)

spatstat/spatstat.geom documentation built on June 14, 2025, 5:50 a.m.