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.
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.