spdep (version 1.3-6)

read.gwt2nb: Read and write spatial neighbour files

Description

The "gwt" functions read and write GeoDa GWT files (the example file baltk4.GWT was downloaded from the site given in the reference), and the "dat" functions read and write Matlab sparse matrix files as used by James LeSage's Spatial Econometrics Toolbox (the example file wmat.dat was downloaded from the site given in the reference). The body of the files after any headers should have three columns separated by white space, and the third column must be numeric in the locale of the reading platform (correct decimal separator).

Usage

read.gwt2nb(file, region.id=NULL)
write.sn2gwt(sn, file, shpfile=NULL, ind=NULL, useInd=FALSE, legacy=FALSE)
read.dat2listw(file)
write.sn2dat(sn, file)
read.swmdbf2listw(fn, region.id=NULL, style=NULL, zero.policy=NULL)
read_swm_dbf(fn)
write.sn2DBF(sn, file)

Value

read.gwt2nb returns a neighbour "nb" object with the generalised weights stored as a list element called "dlist" of the "GeoDa" attribute; read.swmdbf2listw returns a "listw" object read from a DBF file exported from an ArcGIS SWM object.

Arguments

file, fn

name of file with weights data

region.id

a character vector of region IDs - for ArcGIS SWM DBFs, the values must be character integers (only numbers not starting with zero)

sn

a spatial.neighbour object

shpfile

character string: if not given Shapefile name taken from GWT file for this dataset

ind

character string: region id indicator field name

useInd

default FALSE, if TRUE, write region.id attribute ID key tags to output file (use in OpenGeoDa will depend on the shapefile having the field named in the ind argument matching the exported tags)

legacy

default FALSE; if TRUE, header has single field with number of observations only

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

Author

Roger Bivand

Details

Attempts to honour the region.id argument given when reading GWT and SWM/DBF files. If the region IDs given in region.id= do not match the origins or destinations in the GWT file, an error or warning will be thrown, which should be considered carefully. read_swm_dbf is a simplified interface to read.swmdbf2listw When no-neighbour observations are present, it is advised that region.id= be given in read.swmdbf2listw; while the function should read correctly if the minimum and maximum IDs are present as observations with neighbours without region.id= set, reading using read.swmdbf2listw will fail when the minimum or maximum ID observations have no neighbours and region.id= is not given.

References

Luc Anselin (2003) GeoDa 0.9 User's Guide, pp. 80--81, Spatial Analysis Laboratory, Department of Agricultural and Consumer Economics, University of Illinois, Urbana-Champaign, http://geodacenter.github.io/docs/geoda093.pdf; also material formerly at spatial-econometrics.com/data/contents.html

See Also

read.gal

Examples

data(baltimore, package="spData")
STATION <- baltimore$STATION
gwt1 <- read.gwt2nb(system.file("weights/baltk4.GWT", package="spData")[1],
 STATION)
cat(paste("Neighbours list symmetry;", is.symmetric.nb(gwt1, FALSE, TRUE),
 "\n"))
listw1 <- nb2listw(gwt1, style="B", glist=attr(gwt1, "GeoDa")$dist)
tmpGWT <- tempfile()
write.sn2gwt(listw2sn(listw1), tmpGWT)
gwt2 <- read.gwt2nb(tmpGWT, STATION)
cat(paste("Neighbours list symmetry;", is.symmetric.nb(gwt2, FALSE, TRUE),
 "\n"))
diffnb(gwt1, gwt2)
data(oldcol)
tmpMAT <- tempfile()
COL.W <- nb2listw(COL.nb)
write.sn2dat(listw2sn(COL.W), tmpMAT)
listwmat1 <- read.dat2listw(tmpMAT)
diffnb(listwmat1$neighbours, COL.nb, verbose=TRUE)
listwmat2 <- read.dat2listw(system.file("etc/weights/wmat.dat", 
 package="spdep")[1])
diffnb(listwmat1$neighbours, listwmat2$neighbours, verbose=TRUE)
if (require("foreign", quietly=TRUE)) {
nc_sf <- sf::st_read(system.file("gpkg/nc.gpkg", package="sf")[1])
nc_sf$UniqueID <- 1:nrow(nc_sf)
fn <- system.file("etc/misc/nc_contiguity_unique_id.dbf", package="spdep")[1]
nc1 <- read.swmdbf2listw(fn, style="B")
nc1
nc1a <- read.swmdbf2listw(fn, region.id=as.character(nc_sf$UniqueID),
 style="B")
all.equal(nc1, nc1a)
fn <- system.file("etc/misc/nc_contiguity_unique_id_islands.dbf",
 package="spdep")[1]
try(nc1i <- read.swmdbf2listw(fn, style="B"))
nc1i <- read.swmdbf2listw(fn, style="B", zero.policy=TRUE)
nc1ia <- read.swmdbf2listw(fn, region.id=as.character(nc_sf$UniqueID),
 style="B", zero.policy=TRUE)
nc1ia
all.equal(nc1i, nc1ia)
(GDAL37 <- as.numeric_version(unname(sf_extSoftVersion()["GDAL"])) >= "3.7.0")
file <- "etc/shapes/california.gpkg.zip"
zipfile <- system.file(file, package="spdep")
if (GDAL37) {
    cal <- st_read(zipfile)
} else {
    td <- tempdir()
    bn <- sub(".zip", "", basename(file), fixed=TRUE)
    target <- unzip(zipfile, files=bn, exdir=td)
    cal <- st_read(target)
}
fn <- system.file("etc/misc/contiguity_myid.dbf", package="spdep")[1]
cal1 <- read.swmdbf2listw(fn, style="B")
cal1a <- read.swmdbf2listw(fn, region.id=as.character(cal$MYID), style="B")
all.equal(cal1, cal1a)
fn <- system.file("etc/misc/contiguity_unique_id.dbf", package="spdep")[1]
cal2 <- read.swmdbf2listw(fn, style="B")
cal2a <- read.swmdbf2listw(fn, region.id=as.character(cal$UniqueID), style="B")
all.equal(cal2, cal2a)
fn <- system.file("etc/misc/contiguity_unique_id_islands.dbf", package="spdep")[1]
try(cal3i <- read.swmdbf2listw(fn, style="B"))
cal3i <- read.swmdbf2listw(fn, style="B", zero.policy=TRUE)
cal3ia <- read.swmdbf2listw(fn, region.id=as.character(cal$UniqueID), style="B", zero.policy=TRUE)
all.equal(cal3i, cal3ia)
cal1a_1n_nb <- cal1a$neighbours
cal1a_1n_nb <- droplinks(cal1a_1n_nb, drop=c("158", "180", "215"), sym=TRUE)
cal1a_1n <- nb2listw(cal1a_1n_nb, style="B", zero.policy=TRUE)
cal1a_1n_sn <- listw2sn(cal1a_1n)
file <- tempfile(fileext=".dbf")
write.sn2DBF(cal1a_1n_sn, file)
cal1a_1n_rt <- read.swmdbf2listw(file, region.id=as.character(cal$MYID),
 style="B", zero.policy=TRUE)
all.equal(cal1a_1n$neighbours, cal1a_1n_rt$neighbours)
all.equal(cal1a_1n$weights, cal1a_1n_rt$weights, check.attributes=FALSE)
cal1_1n_rt <- read.swmdbf2listw(file, style="B", zero.policy=TRUE)
all(isTRUE(all.equal(cal1a_1n$neighbours, cal1_1n_rt$neighbours)))
all(isTRUE(all.equal(cal1a_1n$weights, cal1_1n_rt$weights)))

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