nb.set.operations {spdep} | R Documentation

## Set operations on neighborhood objects

### Description

Set operations on neighbors list objects

### Usage

    intersect.nb(nb.obj1,nb.obj2)
    union.nb(nb.obj1,nb.obj2)
    setdiff.nb(nb.obj1,nb.obj2)
    complement.nb(nb.obj)

### Arguments

`nb.obj` | a neighbor list created from any of the neighborhood list funtions
`nb.obj1` | a neighbor list created from any of the neighborhood list funtions
`nb.obj2` | a neighbor list created from any of the neighborhood list funtions

### Details

These functions perform set operations on each element of a neighborlist. The arguments must be neighbor lists created from the same coordinates, and the region.id attributes must be identical.

### Value

`nb.obj` | A new neighborlist created from the set operations on the input neighbor list(s)

### Author(s)

Nicholas Lewin-Koh kohnicho@comp.nus.edu.sg

### See Also

`intersect.nb`, `union.nb`, `setdiff.nb`

### Examples

    data(columbus)
    col.tri.nb <- tri2nb(coords)
    oldpar <- par(mfrow=c(1,2))
    col.soi.nb <- graph2nb(soi.graph(col.tri.nb, coords))
    library(maptools)
    plot(polys, border="grey", forcefill=FALSE)
    plot(col.soi.nb, coords, add=TRUE)
    title(main="Sphere of Influence Graph")
    plot(polys, border="grey", forcefill=FALSE)
    plot(complement.nb(col.soi.nb), coords, add=TRUE)
    title(main="Complement of Sphere of Influence Graph")
    par(mfrow=c(2,2))
    col2 <- droplinks(col.gal.nb, 21)
    plot(intersect.nb(col.gal.nb, col2), coords)
    title(main="Intersect")
    plot(union.nb(col.gal.nb, col2), coords)
    title(main="Union")
    plot(setdiff.nb(col.gal.nb, col2), coords)
    title(main="Set diff")
    par(oldpar)

[Package spdep version 0.3-25 Index]