spatstat (version 1.63-3)

plot.psp: plot a Spatial Line Segment Pattern

Description

Plot a two-dimensional line segment pattern

Usage

# S3 method for psp
plot(x, …, main, add=FALSE,
                     show.all=!add, show.window=show.all,
                     which.marks=1,
                     style=c("colour", "width", "none"),
                     col=NULL, 
                     ribbon=show.all,
                     ribsep=0.15, ribwid=0.05, ribn=1024,
                     do.plot=TRUE)

Arguments

x

The line segment pattern to be plotted. An object of class "psp", or data which can be converted into this format by as.psp().

…

extra arguments that will be passed to the plotting functions segments (to plot the segments) and plot.owin (to plot the observation window).

main

Character string giving a title for the plot.

add

Logical. If TRUE, the current plot is not erased; the segments are plotted on top of the current plot, and the window is not plotted (by default).

show.all

Logical value specifying whether to plot everything including the window, main title, and colour ribbon.

show.window

Logical value specifying whether to plot the window.

which.marks

Index determining which column of marks to use, if the marks of x are a data frame. A character string or an integer. Defaults to 1 indicating the first column of marks.

style

Character string specifying how to represent the mark value of each segment. If style="colour" (the default) segments are coloured according to their mark value. If style="width", segments are drawn with a width proportional to their mark value. If style="none" the mark values are ignored.

col

Colour information. If style="width" or style="none", then col should be a single value, interpretable as a colour; the line segments will be plotted using this colour. If style="colour" and x has marks, then the mark values will be mapped to colours using the information in col, which should be a colour map (object of class "colourmap") or a vector of colour values.

ribbon

Logical flag indicating whether to display a ribbon showing the colour map (in which mark values are associated with colours) when style="colour".

ribsep

Factor controlling the space between the ribbon and the image.

ribwid

Factor controlling the width of the ribbon.

ribn

Number of different values to display in the ribbon.

do.plot

Logical value indicating whether to actually perform the plot.

Value

(Invisibly) a colour map object specifying the association between marks and colours, if any. The return value also has an attribute "bbox" giving a bounding box for the plot.

Details

This is the plot method for line segment pattern datasets (of class "psp", see psp.object). It plots both the observation window Window(x) and the line segments themselves.

Plotting of the window Window(x) is performed by plot.owin. This plot may be modified through the ... arguments.

Plotting of the segments themselves is performed by the standard R function segments. Its plotting behaviour may also be modified through the ... arguments.

If the segments do not have marks (i.e. if marks(x) = NULL) then

There are three different styles of plotting which apply when the segments have marks (i.e. when marks(x) is not null):

style="colour" (the default):

Segments are plotted with different colours depending on their mark values. The colour map, associating mark values with colours, is determined by the argument col. The colour map will be displayed as a vertical colour ribbon to the right of the plot, if ribbon=TRUE (the default).

style="width":

Segments are plotted with different widths depending on their mark values. The width map, associating mark values with line widths, is determined by leg.scale (see plot.linim). The width map will be displayed as a vertical stack of lines to the right of the plot, if legend=TRUE (the default).

style="none":

Mark information is ignored.

If marks(x) is a data frame, the default is to use the first column of marks(x) to determine the colours. To specify another column, use the argument which.marks.

See Also

psp.object, plot, par, plot.owin, text.psp, symbols

Examples

# NOT RUN {
  X <- psp(runif(20), runif(20), runif(20), runif(20), window=owin())
  plot(X)
  plot(X, lwd=3)
  lettuce <- sample(letters[1:4], 20, replace=TRUE)
  marks(X) <- data.frame(A=1:20, B=factor(lettuce))
  plot(X)
  plot(X, which.marks="B")
  plot(X, style="width", col="grey")
# }