plot.nb: Plot a neighbours list

In spdep: Spatial Dependence: Weighting Schemes, Statistics and Models

Description

A function to plot a neighbours list given point coordinates to represent the region in two dimensions; plot.listw is a wrapper that passes its neighbours component to plot.nb.

Usage

## S3 method for class 'nb'
plot(x, coords, col="black", points=TRUE, add=FALSE, arrows=FALSE,
 length=0.1, xlim=NULL, ylim=NULL, ...)
## S3 method for class 'listw'
plot(x, coords, col="black", points=TRUE, add=FALSE, arrows=FALSE,
 length=0.1, xlim=NULL, ylim=NULL, ...)

Arguments

x	an object of class nb or (for plot.listw) class listw
coords	matrix of region point coordinates
col	plotting colour
points	(logical) add points to plot
add	(logical) add to existing plot
arrows	(logical) draw arrowheads for asymmetric neighbours
length	length in plot inches of arrow heads drawn for asymmetric neighbours lists
xlim, ylim	plot window bounds
...	further graphical parameters as in par(..)

Author(s)

Roger Bivand [e-mail]

See Also

summary.nb

Examples

example(columbus)
coords <- coordinates(columbus)
plot(col.gal.nb, coords)
title(main="GAL order 1 links with first nearest neighbours in red")
col.knn <- knearneigh(coords, k=1)
plot(knn2nb(col.knn), coords, add=TRUE, col="red", length=0.08)

Example output

Loading required package: sp
Loading required package: Matrix

colmbs> require(maptools)
Loading required package: maptools
Checking rgeos availability: TRUE

colmbs> columbus <- readShapePoly(system.file("etc/shapes/columbus.shp",
colmbs+  package="spdep")[1])

colmbs> col.gal.nb <- read.gal(system.file("etc/weights/columbus.gal",
colmbs+  package="spdep")[1])
Warning message:
use rgdal::readOGR or sf::st_read 

spdep documentation built on Aug. 19, 2017, 3:01 a.m.