# zones

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

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.

- Keywords
- file

##### Usage

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

##### 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

##### Value

A list containing

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 x 2`

table of the center and the radial area for each zone

`n x n`

inter-point distance matrix of the centroids

##### 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

```
# NOT RUN {
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)
# }
```

*Documentation reproduced from package SpatialEpi, version 1.2.3, License: GPL-2*