aggregate.nb {spdep} | R Documentation

## Aggregate a spatial neighbours object

### Description

The method aggregates a spatial neighbours object, creating a new object listing the neighbours of the aggregates.

### Usage

    ## S3 method for class 'nb':
    aggregate(x, IDs, remove.self = TRUE, ...)

### Arguments

`x` | an nb neighbour object
`IDs` | a character vector of IDs grouping the members of the neighbour object
`remove.self` | default TRUE: remove self-neighbours resulting from aggregation
`...` | unused - arguments passed through

### Value

an nb neighbour object

### Note

Method suggested by Roberto Patuelli

### Author(s)

Roger Bivand Roger.Bivand@nhh.no

### Examples

    data(used.cars)
    data(state)
    cont_st <- match(attr(usa48.nb, "region.id"), state.abb)
    cents <- as.matrix(as.data.frame(state.center))[cont_st,]
    opar <- par(mfrow=c(2,1))
    plot(usa48.nb, cents, xlim=c(-125, -65), ylim=c(25, 50))
    IDs <- as.character(state.division[cont_st])
    agg_cents <- aggregate(cents, list(IDs), mean)
    agg_nb <- aggregate(usa48.nb, IDs)
    plot(agg_nb, agg_cents[, 2:3], xlim=c(-125, -65), ylim=c(25, 50))
    text(agg_cents[, 2:3], agg_cents[, 1], cex=0.6)
    par(opar)

[Package spdep version 0.4-56 Index]