spdep (version 0.5-82)

nc.sids: North Carolina SIDS data

Description

(Use example(nc.sids) to read the data set from shapefile, together with import of two different list of neighbours).

The nc.sids data frame has 100 rows and 21 columns. It contains data given in Cressie (1991, pp. 386-9), Cressie and Read (1985) and Cressie and Chan (1989) on sudden infant deaths in North Carolina for 1974-78 and 1979-84. The data set also contains the neighbour list given by Cressie and Chan (1989) omitting self-neighbours (ncCC89.nb), and the neighbour list given by Cressie and Read (1985) for contiguities (ncCR85.nb). The data are ordered by county ID number, not alphabetically as in the source tables sidspolys is a "polylist" object of polygon boundaries, and sidscents is a matrix of their centroids.

Usage

data(nc.sids)

source

Cressie, N (1991), Statistics for spatial data. New York: Wiley, pp. 386--389; Cressie, N, Chan NH (1989) Spatial modelling of regional variables. Journal of the American Statistical Association, 84, 393--401; Cressie, N, Read, TRC (1985) Do sudden infant deaths come in clusters? Statistics and Decisions Supplement Issue 2, 333--349; http://sal.agecon.uiuc.edu/datasets/sids.zip.

Examples

require(maptools)
nc.sids <- readShapePoly(system.file("etc/shapes/sids.shp", package="spdep")[1],
  ID="FIPSNO", proj4string=CRS("+proj=longlat +ellps=clrk66"))
rn <- sapply(slot(nc.sids, "polygons"), function(x) slot(x, "ID"))
ncCC89_nb <- read.gal(system.file("etc/weights/ncCC89.gal", package="spdep")[1],
  region.id=rn)
ncCR85_nb <- read.gal(system.file("etc/weights/ncCR85.gal", package="spdep")[1],
  region.id=rn)
plot(nc.sids, border="grey")
plot(ncCR85_nb, coordinates(nc.sids), add=TRUE, col="blue")
plot(nc.sids, border="grey")
plot(ncCC89_nb, coordinates(nc.sids), add=TRUE, col="blue")