SpatialEpi (version 1.2.8)

zones: Create set of all single zones and output geographical information

Description

Based on the population counts and centroid coordinates of each of n areas, output the set of n.zones single zones as defined by Kulldorff and other geographical information.

Usage

zones(geo, population, pop.upper.bound)

Value

A list containing

nearest.neighbors

list of n elements, where each element is a vector of the nearest neighbors in order of distance up until pop.upper.bound of the total population is attained

cluster.coords

n.zones x 2 table of the center and the radial area for each zone

dist

n x n inter-point distance matrix of the centroids

Arguments

geo

n x 2 table of the (x,y)-coordinates of the area centroids

population

a vector of population counts of each area

pop.upper.bound

maximum proportion of study region each zone can contain

Author

Albert Y. Kim

References

Kulldorff, M. (1997) A spatial scan statistic. Communications in Statistics: Theory and Methods, 26, 1481--1496. Kulldorff M. and Nagarwalla N. (1995) Spatial disease clusters: Detection and Inference. Statistics in Medicine, 14, 799--810.

Examples

data(pennLC)
geo <- pennLC$geo[,2:3]
geo <- latlong2grid(geo)
population <- tapply(pennLC$data$population, pennLC$data$county, sum)
pop.upper.bound <- 0.5
geo.info <- zones(geo, population, pop.upper.bound)