R: extract info about voronoi cells

cells {interp} | R Documentation

## extract info about voronoi cells

### Description

This function returns some info about the cells of a voronoi mosaic, including the coordinates of the vertices and the cell area.

### Usage

    cells(voronoi.obj)

### Arguments

`voronoi.obj` | object of class `voronoi`

### Details

The function calculates the neighbourhood relations between the underlying triangulation and translates it into the neighbourhood relations between the voronoi cells.

### Value

retruns a list of lists, one entry for each voronoi cell which contains

`cell` | cell index
`center` | cell 'center'
`neighbours` | neighbour cell indices
`nodes` | 2 times `nnb` matrix with vertice coordinates
`area` | cell area

### Note

outer cells have `area=NA`, currently also `nodes=NA` which is not really useful – to be done later

### Author(s)

A. Gebhardt

### See Also

`voronoi.mosaic`, `voronoi.area`

### Examples

    data(tritest)
    tritest.vm <- voronoi.mosaic(tritest$x,tritest$y)
    tritest.cells <- cells(tritest.vm)
    # higlight cell 12:
    plot(tritest.vm)
    polygon(t(tritest.cells[[12]]$nodes),col="green")
    # put cell area into cell center:
    text(tritest.cells[[12]]$center[1],
         tritest.cells[[12]]$center[2],
         tritest.cells[[12]]$area)

[Package interp version 1.1-1 Index]