listw2sn: Spatial neighbour sparse representation
In spdep: Spatial Dependence: Weighting Schemes, Statistics

listw2sn

R Documentation

Spatial neighbour sparse representation

Description

The function makes a "spatial neighbour" object representation (similar to the S-PLUS spatial statististics module representation of a "listw" spatial weights object. sn2listw() is the inverse function to listw2sn(), creating a "listw" object from a "spatial neighbour" object.

Usage

listw2sn(listw)
sn2listw(sn, style = NULL, zero.policy = NULL, from_mat2listw=FALSE)

Arguments

`listw`	a `listw` object from for example `nb2listw`
`sn`	a `spatial.neighbour` object
`style`	default NULL, missing, set to "M" and warning given; if not "M", passed to `nb2listw` to re-build the object
`zero.policy`	default NULL, use global option value; if FALSE stop with error for any empty neighbour sets, if TRUE permit the weights list to be formed with zero-length weights vectors
`from_mat2listw`	default FALSE, set TRUE if called from `mat2listw`

Value

listw2sn()returns a data frame with three columns, and with class spatial.neighbour:

`from`	region number id for the start of the link (S-PLUS row.id)
`to`	region number id for the end of the link (S-PLUS col.id)
`weights`	weight for this link

Author(s)

Roger Bivand Roger.Bivand@nhh.no

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])
col.listw <- nb2listw(col.gal.nb)
col.listw$neighbours[[1]]
col.listw$weights[[1]]
col.sn <- listw2sn(col.listw)
str(col.sn)

spdep documentation built on Sept. 1, 2025, 1:09 a.m.