R: Plot Dirchlet (Voronoi) tiles

plot.tile.list {deldir}

R Documentation

Plot Dirchlet (Voronoi) tiles

Description

A method for plot. Plots (sequentially) the tiles associated with each point in the set being tessellated.

Usage

## S3 method for class 'tile.list'
plot(x, verbose = FALSE, close = FALSE, pch = 1,
                         fillcol = getCol(x,warn=warn),col.pts = NULL,
                         border=NULL, showpoints = TRUE, add = FALSE,
                         asp = 1, clipp = NULL, xlab = "x", ylab = "y",
                         main = "", warn = FALSE, ...)

Arguments

`x`	A list of the tiles in a tessellation, as produced the function `tile.list()`.
`verbose`	Logical scalar; if `TRUE` the tiles are plotted one at a time (with a “Go?” prompt after each) so that the process can be watched.
`close`	Logical scalar; if `TRUE` the outer edges of of the tiles (i.e. the edges which are contained in the enclosing rectangle) are drawn. Otherwise tiles on the periphery of the tessellation are left “open”.
`pch`	The plotting character (or vector of plotting characters) with which to plot the points of the pattern which was tessellated. Ignored if `showpoints` is `FALSE`.
`fillcol`	Optional vector (possibly of length 1, i.e. a scalar) whose entries can be interpreted as colours by `col2rgb()`. The i-th entry indicates with which colour to fill the i-th tile. Note that an `NA` entry indicates the use of no colour at all. This argument will be replicated to have length equal to the number of tiles.
`col.pts`	Optional vector like unto `fillcol` whose entries can be interpreted as colours by `col2rgb()`. The i-th entry indicates with which colour to plot the i-th point. This argument will be replicated to have length equal to the number of tiles. Ignored if `showpoints` is `FALSE`.
`border`	A scalar indicating the colour with which to plot the tile boundaries. Defaults to black unless all of the fill colours specified by `fillcol` are black, in which case it defaults to white. If `length(border) > 1` then an error is given.
`showpoints`	Logical scalar; if `TRUE` the points of the pattern which was tesselated are plotted.
`add`	Logical scalar; should the plot of the tiles be added to an existing plot?
`asp`	The aspect ratio of the plot; integer scalar or `NA`. Set this argument equal to `NA` to allow the data to determine the aspect ratio and hence to make the plot occupy the complete plotting region in both `x` and `y` directions. This is inadvisable; see the Warnings.
`clipp`	An object specifying a polygon to which the tessellation being plotted should be clipped. It should consist either of: a list containing two components x and y giving the coordinates of the vertices of a single polygon. The last vertex should not repeat the first vertex. Or: a list of list(x,y) structures giving the coordinates of the vertices of several polygons. If this argument is provided then the plot of the tessellation is “clipped” to the polygon specified by `clipp`.
`xlab`	Label for the `x`-axis (used only if `add` is `FALSE`).
`ylab`	Label for the `y`-axis (used only if `add` is `FALSE`).
`main`	A title for the plot (used only if `add` is `FALSE`).
`warn`	Logical scalar passed to the internal function `getCol()`. Should a warning be issued if the `z` components of the entries of `x` cannot all be interpreted as colours. See Details.
`...`	Optional arguments; not used. There for consistency with the generic `plot` function.

Value

NULL; side effect is a plot.

Warnings

The behaviour of this function with respect to “clipping” has changed substantially since the previous release of deldir, i.e. 1.1-0. The argument clipwin has been re-named clipp (“p” for “polygon”). Clipping is now effected via the new package polyclip. The spatstat package is no longer used. The argument use.gpclib has been eliminated, since gpclib (which used to be called upon by spatstat has been superceded by polyclip which has an unrestrictive license.
As of release 0.1-1 of the deldir package, the argument fillcol to this function replaces the old argument polycol, but behaves somewhat differently.
The argument showrect which was present in versions of this function prior to release 0.1-1 has been eliminated. It was redundant.
As of release 0.1-1 the col.pts argument might behave somewhat differently from how it behaved in the past.
The arguments border, clipp, and warn are new as of release 0.1-1.
Users, unless they really understand what they are doing and why they are doing it, are strongly advised not to set the value of asp but rather to leave asp equal to its default value of 1. Any other value distorts the tesselation and destroys the perpendicular appearance of lines which are indeed perpendicular. (And conversely can cause lines which are not perpendicular to appear as if they are.)

Notes

If clipp is not NULL and showpoints is TRUE then it is possible that some of the points “shown” will not fall inside any of the plotted tiles. (This will happen if the parts of the tiles in which they fall have been “clipped” out.) If a tile is clipped out completely then the point which determines that tile is not plotted irrespective of the value of showpoints.
The new behaviour in respect of the colours with which to fill the plotted tiles, and the argument clipp were added at the request of Chris Triggs.
The argument asp was added at the request of Zubin Dowlaty.

Author(s)

Rolf Turner r.turner@auckland.ac.nz https://www.stat.auckland.ac.nz/~rolf

Examples

  set.seed(42)
  x <- runif(20)
  y <- runif(20)
  z <- deldir(x,y,rw=c(0,1,0,1))
  w <- tile.list(z)
  plot(w)
  ccc <- heat.colors(20) # Or topo.colors(20), or terrain.colors(20)
                         # or cm.colors(20), or rainbow(20).
  plot(w,fillcol=ccc,close=TRUE)
  if(require(polyclip)) {
     CP <- list(x=c(0.49,0.35,0.15,0.20,0.35,0.42,
                          0.43,0.62,0.46,0.63,0.82,0.79),
                      y=c(0.78,0.86,0.79,0.54,0.58,0.70,
                          0.51,0.46,0.31,0.20,0.37,0.54))
     plot(w,clipp=CP,showpoints=FALSE,fillcol=topo.colors(20))
  }

[Package deldir version 0.1-9 Index]