smerc (version 1.8.3)

elliptic.zones: Determine zones for elliptic.test

Description

elliptic.zones constructs the elliptical zones for elliptic.test.

Usage

elliptic.zones(
  coords,
  pop,
  ubpop = 0.5,
  shape = c(1, 1.5, 2, 3, 4, 5),
  nangle = c(1, 4, 6, 9, 12, 15)
)

Value

A list with all distinct zones, the associated shape parameters, and the associated angle parameters.

Arguments

coords

An \(n \times 2\) matrix of centroid coordinates for the regions in the form (x, y) or (longitude, latitude) is using great circle distance.

pop

The population size associated with each region.

ubpop

The upperbound of the proportion of the total population to consider for a cluster.

shape

The ratios of the major and minor axes of the desired ellipses.

nangle

The number of angles (between 0 and 180) to consider for each shape.

References

Kulldorff, M., Huang, L., Pickle, L. and Duczmal, L. (2006) An elliptic spatial scan statistic. Statististics in Medicine, 25:3929-3943. <doi:10.1002/sim.2490>

Examples

if (FALSE) {
data(nydf)
coords <- with(nydf, cbind(longitude, latitude))
out <- elliptic.zones(
  coords = coords, pop = nydf$pop,
  shape = 1.5, nangle = 4
)
}