plot.deldir {deldir}R Documentation

Produce a plot of the Delaunay triangulation and Dirichlet (Voronoi) tesselation of a planar point set, as constructed by the function deldir.

Description

This is a method for plot.

Usage

## S3 method for class 'deldir':
plot(x,add=FALSE,wlines=c('both','triang','tess'),
                      wpoints=c('both','real','dummy','none'),
                      number=FALSE,cex=1,nex=1,col=NULL,lty=NULL,
                      pch=NULL,xlim=NULL,ylim=NULL,xlab='x',ylab='y',...)

Arguments

x An object of class "deldir" as constructed by the function deldir.
add logical argument; should the plot be added to an existing plot?
wlines "which lines?". I.e. should the Delaunay triangulation be plotted (wlines='triang'), should the Dirichlet tessellation be plotted (wlines='tess'), or should both be plotted (wlines='both', the default) ?
wpoints "which points?". I.e. should the real points be plotted (wpoints='real'), should the dummy points be plotted (wpoints='dummy'), should both be plotted (wpoints='both', the default) or should no points be plotted (wpoints='none')?
number Logical argument, defaulting to FALSE; if TRUE then the points plotted will be labelled with their index numbers (corresponding to the row numbers of the matrix "summary" in the output of deldir).
cex The value of the character expansion argument cex to be used with the plotting symbols for plotting the points.
nex The value of the character expansion argument cex to be used by the text function when numbering the points with their indices. Used only if number=TRUE.
col the colour numbers for plotting the triangulation, the tesselation, the data points, the dummy points, and the point numbers, in that order; defaults to c(1,1,1,1,1). If fewer than five numbers are given, they are recycled. (If more than five numbers are given, the redundant ones are ignored.)
lty the line type numbers for plotting the triangulation and the tesselation, in that order; defaults to 1:2. If only one value is given it is repeated. (If more than two numbers are given, the redundant ones are ignored.)
pch the plotting symbols for plotting the data points and the dummy points, in that order; may be either integer or character; defaults to 1:2. If only one value is given it is repeated. (If more than two values are given, the redundant ones are ignored.)
xlim the limits on the x-axis. Defaults to rw[1:2] where rw is the rectangular window specification returned by deldir().
ylim the limits on the y-axis. Defaults to rw[3:4] where rw is the rectangular window specification returned by deldir().
xlab label for the x-axis. Defaults to x. Ignored if add=TRUE.
ylab label for the y-axis. Defaults to y. Ignored if add=TRUE.
... Further plotting parameters to be passed to plot() segments() or points(). Unlikely to be used.

Details

The points in the set being triangulated are plotted with distinguishing symbols. By default the real points are plotted as circles (pch=1) and the dummy points are plotted as triangles (pch=2).

Side Effects

A plot of the points being triangulated is produced or added to an existing plot. As well, the edges of the Delaunay triangles and/or of the Dirichlet tiles are plotted. By default the triangles are plotted with solid lines (lty=1) and the tiles with dotted lines (lty=2).

See Also

deldir

Examples

## Not run: 
try <- deldir(x,y,list(ndx=2,ndy=2),c(0,10,0,10))
plot(try)
#
deldir(x,y,list(ndx=4,ndy=4),plot=TRUE,add=TRUE,wl='te',
       col=c(1,1,2,3,4),num=TRUE)
# Plots the tesselation, but does not save the results.
try <- deldir(x,y,list(ndx=2,ndy=2),c(0,10,0,10),plot=TRUE,wl='tr',
              wp='n')
# Plots the triangulation, but not the points, and saves the returned
structure.
## End(Not run)
[Package deldir version 0.0-5 Index]