SpatialEpi (version 1.1)

zones: Create Set of All Zones and Output Geographical Information

Description

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

Usage

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

Arguments

geo

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

area.population

a vector of population counts of each area

pop.upper.bound

maximum proportion of study region each zone can contain

Value

• A list containing
• nearest.neighbors
  a 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
• n.zones
  total number of zones
• cluster.coords
  an n x 2 table of the center and the radial areas for each zone
• dist
  an n x n inter-point distance matrix

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

geo.info <- zones(geo, area.population, pop.upper.bound)

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