deldir (version 0.1-9)

plot.tile.list: 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

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 r

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 th

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

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

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 toclippinghas changed substantially since the previous release ofdeldir, i.e. 1.1-0. The argumentclipwinhas been re-namedclipp(pforpolygon). Clipping is now effected via the new packagepolyclip. Thespatstatpackage is no longer used. The argumentuse.gpclibhas been eliminated, sincegpclib(which used to be called upon byspatstathas been superceded bypolyclipwhich has an unrestrictive license.
• As of release 0.1-1 of thedeldirpackage, the argumentfillcolto this functionreplacesthe old argumentpolycol, but behaves somewhat differently.
• The argumentshowrectwhich 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 thecol.ptsargumentmightbehave somewhat differently from how it behaved in the past.
• The argumentsborder,clipp, andwarnare new as of release 0.1-1.
• Users, unless theyreallyunderstand what they are doing and why they are doing it, arestrongly advisednot to set the value ofaspbut rather to leaveaspequal to its default value of1. 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

• Ifclippis notNULLandshowpointsisTRUEthen it is possible that some of the pointsshownwill not fall inside any of the plotted tiles. (This will happen if the parts of the tiles in which they fall have beenclippedout.) If a tile is clipped outcompletelythen the point which determines that tile isnotplotted irrespective of the value ofshowpoints.
• The new behaviour in respect of the colours with which to fill the plotted tiles, and the argumentclippwere added at the request of Chris Triggs.
• The argumentaspwas added at the request of Zubin Dowlaty.

See Also

deldir(), tile.list() triang.list() plot.triang.list()

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))
  }