1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
|
% Copyright 2001 by Nicholas Lewin-Koh
\name{nb.set.operations}
\alias{intersect.nb}
\alias{union.nb}
\alias{setdiff.nb}
\alias{complement.nb}
\title{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{
\item{nb.obj}{a neighbor list created from any of the neighborhood
list funtions}
\item{nb.obj1}{a neighbor list created from any of the neighborhood
list funtions}
\item{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{
\item{nb.obj}{A new neighborlist created from the set operations on the
input neighbor list(s)}
}
\author{Nicholas Lewin-Koh \email{nikko@hailmail.net}}
\seealso{\code{\link{intersect.nb}}, \code{\link{union.nb}},
\code{\link{setdiff.nb}}}
\examples{
if (require(rgdal, quietly=TRUE)) {
example(columbus, package="spData")
coords <- coordinates(columbus)
col.tri.nb <- tri2nb(coords)
oldpar <- par(mfrow=c(1,2))
col.soi.nb <- graph2nb(soi.graph(col.tri.nb, coords))
plot(columbus, border="grey")
plot(col.soi.nb, coords, add=TRUE)
title(main="Sphere of Influence Graph")
plot(columbus, border="grey")
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)
}
}
\keyword{spatial}
|
