deldir (version 0.1-25)

tilePerim: Calculate tile perimeters.

Description

Calculates the perimeters of all of the Dirichlet (Voronoi) tiles in a tessellation of a set of planar points. Also calculates the sum and the mean of these perimeters.

Usage

tilePerim(object,inclbdry=TRUE)

Arguments

object

An object of class tile.list (as produced by tile.list() specifying the Dirichlet (Voronoi) tiles in a tessellation of a set of planar points.

inclbdry

Logical scalar. Should boundary segments (edges of tiles at least one of whose endpoints lies on the enclosing rectangle rw (see deldir()) be included in the perimeter?

Value

A list with components

perimeters

A vector consisting of the values of the perimeters of the Dirichlet tiles in the tessellation.

totalPerim

The sum of perimeters.

meanPerim

The mean of perimeters.

See Also

tile.list(), plot.tile.list()

Examples

Run this code
# NOT RUN {
    x <- runif(20)
    y <- runif(20)
    z <- deldir(x,y,rw=c(0,1,0,1))
    w <- tile.list(z)
    p1 <- tilePerim(w)
    p0 <- tilePerim(w,inclbdry=FALSE)
    p1$totalPerim - p0$totalPerim # Get 4 = the perimeter of rw.
    ss <- apply(as.matrix(z$dirsgs[,1:4]),1,
                function(x){(x[1]-x[3])^2 + (x[2]-x[4])^2})
    2*sum(sqrt(ss)) - p0$totalPerim # Get 0; in tilePerim() each interior
                                    # edge is counted twice.
# }

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