spdep (version 0.5-74)

listw2sn: 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. The as.spam.listw method converts a "listw" object to a sparse matrix as defined in the spam package, using listw2sn().

Usage

listw2sn(listw)
sn2listw(sn)
as.spam.listw(listw)

Arguments

listw

a listw object from for example nb2listw

sn

a spatial.neighbour object

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

See Also

nb2listw

Examples

example(columbus)
col.listw <- nb2listw(col.gal.nb)
col.listw$neighbours[[1]]
col.listw$weights[[1]]
col.sn <- listw2sn(col.listw)
str(col.sn)
col.sp <- as.spam.listw(col.listw)
str(col.sp)