R: Compute Geary's C

geary {spdep} | 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∑_{i=1}^{n}∑_{j=1}^{n}w_{ij}} \frac{∑_{i=1}^{n}∑_{j=1}^{n}w_{ij}(x_i-x_j)^2}{∑_{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=NULL)

### 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 NULL, 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.

### See Also

`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)))

[Package spdep version 0.6-13 Index]