knn2nb function

Neighbours list from knn object

The function converts a knn object returned by knearneigh

into a neighbours list of class nb with a list of integer vectors containing neighbour region number ids.

knn2nb(knn, row.names = NULL, sym = FALSE)

Arguments

• knn: A knn object returned by knearneigh
• row.names: character vector of region ids to be added to the neighbours list as attribute region.id, default seq(1, nrow(x))
• sym: force the output neighbours list to symmetry

Returns

The function returns an object of class nb with a list of integer vectors containing neighbour region number ids. See card for details of nb objects.

Author(s)

Roger Bivand Roger.Bivand@nhh.no

See Also

knearneigh, card

Examples

columbus <- st_read(system.file("shapes/columbus.gpkg", package="spData")[1], quiet=TRUE)
coords <- st_coordinates(st_centroid(columbus))
col.knn <- knearneigh(coords, k=4)
plot(st_geometry(columbus), border="grey")
plot(knn2nb(col.knn), coords, add=TRUE)
title(main="K nearest neighbours, k = 4")
# example of reading points with readr::read_csv() yielding a tibble
load(system.file("etc/misc/coords.rda", package="spdep"))
class(coords)
knn2nb(knearneigh(coords, k=4))