R: Create a list of tiles in a tessellation.

tile.list {deldir}

R Documentation

Create a list of tiles in a tessellation.

Description

For each point in the set being tessellated produces a list entry describing the Dirichlet/Voronoi tile containing that point.

Usage

 tile.list(object)

Arguments

object An object of class deldir as produced by the function deldir().

Value

A list with one entry for each of the points in the set being tesselated. Each entry is in turn a list with components

`pt`	The coordinates of the point whose tile is being described.
`x`	The `x` coordinates of the vertices of the tile, in anticlockwise order.
`y`	The `y` coordinates of the vertices of the tile, in anticlockwise order.
`bp`	Vector of logicals indicating whether the tile vertex is a ``real'' vertex, or a boundary point, i.e. a point where the tile edge intersects the boundary of the enclosing rectangle

Warning

The set of vertices of each tile may be ``incomplete''. Only vertices which lie within the enclosing rectangle, and ``boundary points'' are listed.

Note that the enclosing rectangle may be specified by the user in the call to deldir().

In contrast to the previous version of deldir, the corners of the enclosing rectangle are now include as vertices of tiles. I.e. a tile which in fact extends beyond the rectangular window and contains a corner of that window will have that corner added to its list of vertices. Thus when the corresponding polygon is plotted, the result is the intersection of the tile with the enclosing rectangular window.

Author(s)

Rolf Turner

Examples

        x <- runif(20)
        y <- runif(20)
        z <- deldir(x,y)
        w <- tile.list(z)

        z <- deldir(x,y,rw=c(0,1,0,1))
        w <- tile.list(z)

        z <- deldir(x,y,rw=c(0,1,0,1),dpl=list(ndx=2,ndy=2))
        w <- tile.list(z)

[Package deldir version 0.0-5 Index]