power_diagram {transport}

Compute the Power Diagram of Weighted Sites in 2-Dimensional Space

Description

Compute the power diagram of weighted sites in 2-dimensional space.

Usage

power_diagram(xi, eta, w, rect = NA)
## S3 method for class 'power_diagram'
plot(x, weights=FALSE, add=FALSE, col=4, lwd=1.5, ...)

Arguments

xi, eta, w

vectors of equal length, where xi, eta are the coordinates of the sites and w are the corresponding weights.

rect

vetor of length 4. To get a finite representation of the power diagram, it will be intersected with the rectangle [rect[1],rect[2]] \times [rect[3],rect[4]]. Defaults to c(min(xi),max(xi),min(eta),max(eta)).

x

a power diagram as returned from power_diagram.

weights

logical. If TRUE, weights of non-redundant sites with non-negative weight are represented as circles whose radii are equal to the square roots of the corresponding weights.

add

logical. Should the power diagram be plotted on top of current graphics?

col

the color of the cell boundaries.

lwd, ...

further arguments graphic parameters used by plot.default.

Details

The function power_diagram implements an algorithm by Edelsbrunner and Shah (1996) which computes regular triangulations and thus its dual representation, the power diagram. For point location, an algorithm devised by Devillers (2002) is used.

Author(s)

Björn Bähre [e-mail]
(slightly modified by Dominic Schuhmacher [e-mail])

References

H. Edelsbrunner, N. R. Shah (1996), Incremental Topological Flipping Works for Regular Triangulations, Algorithmica 15, 223–241.

O. Devillers (2002), The Delaunay Hierarchy, International Journal of Foundations of Computer Science 13, 163–180.

Examples

    xi <- runif(100)
    eta <- runif(100)
    w <- runif(100,0,0.005)
    x <- power_diagram(xi,eta,w,rect=c(0,1,0,1))
    plot(x,weights=TRUE)