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 0.4-56 Index]