# geary: Compute Geary's C In r-spatial/spdep: Spatial Dependence: Weighting Schemes, Statistics

 geary R Documentation

## Compute Geary's C

### Description

A simple function to compute Geary's C, called by geary.test and geary.mc;

C = \frac{(n-1)}{2\sum_{i=1}^{n}\sum_{j=1}^{n}w_{ij}} \frac{\sum_{i=1}^{n}\sum_{j=1}^{n}w_{ij}(x_i-x_j)^2}{\sum_{i=1}^{n}(x_i - \bar{x})^2} 

geary.intern is an internal function used to vary the similarity criterion.

### Usage

geary(x, listw, n, n1, S0, zero.policy=attr(listw, "zero.policy"))



### Arguments

 x a numeric vector the same length as the neighbours list in listw listw a listw object created for example by nb2listw n number of zones n1 n - 1 S0 global sum of weights zero.policy default attr(listw, "zero.policy") as set when listw was created, if attribute not set, use global option value; if TRUE assign zero to the lagged value of zones without neighbours, if FALSE assign NA

### Value

a list with

 C Geary's C K sample kurtosis of x

### Author(s)

Roger Bivand Roger.Bivand@nhh.no

### References

Cliff, A. D., Ord, J. K. 1981 Spatial processes, Pion, p. 17.

geary.test, geary.mc, sp.mantel.mc

### Examples

data(oldcol)
col.W <- nb2listw(COL.nb, style="W")
str(geary(COL.OLD\$CRIME, col.W, length(COL.nb), length(COL.nb)-1,
Szero(col.W)))


r-spatial/spdep documentation built on April 30, 2024, 9:12 p.m.