listw2sn function

Spatial neighbour sparse representation

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.

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

Returns

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

See Also

nb2listw

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)