plot.nb: Plot a neighbours list

In r-spatial/spdep: Spatial Dependence: Weighting Schemes, Statistics

Plot a neighbours list

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, a Spatial object (points or polygons), or an sfc object (points or polygons)
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

columbus <- st_read(system.file("shapes/columbus.gpkg", package="spData")[1], quiet=TRUE)
col.gal.nb <- read.gal(system.file("weights/columbus.gal", package="spData")[1])
plot(col.gal.nb, st_geometry(columbus))
title(main="GAL order 1 links with first nearest neighbours in red", cex.main=0.6)
plot(col.gal.nb, as(columbus, "Spatial"))
title(main="GAL order 1 links with first nearest neighbours in red", cex.main=0.6)
coords <- st_centroid(st_geometry(columbus), of_largest_polygon=TRUE)
col.knn <- knearneigh(coords, k=1)
plot(knn2nb(col.knn), coords, add=TRUE, col="red", length=0.08)

r-spatial/spdep documentation built on Dec. 3, 2024, 3:27 a.m.