nc.sids {spdep}R Documentation

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)

Format

This data frame contains the following columns:

SP_ID
SpatialPolygons ID
CNTY_ID
county ID
east
eastings, county seat, miles, local projection
north
northings, county seat, miles, local projection
L_id
Cressie and Read (1985) L index
M_id
Cressie and Read (1985) M index
names
County names
AREA
County polygon areas in degree units
PERIMETER
County polygon perimeters in degree units
CNTY_
Internal county ID
NAME
County names
FIPS
County ID
FIPSNO
County ID
CRESS_ID
Cressie papers ID
BIR74
births, 1974-78
SID74
SID deaths, 1974-78
NWBIR74
non-white births, 1974-78
BIR79
births, 1979-84
SID79
SID deaths, 1979-84
NWBIR79
non-white births, 1979-84

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

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)
## Not run: 
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")
## End(Not run)

[Package spdep version 0.4-34 Index]