spdep (version 0.1-10)

geary: 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=FALSE)
geary.intern(x, listw, n, zero.policy, type="geary")

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

if TRUE assign zero to the lagged value of zones without neighbours, if FALSE assign NA

type

"geary" or "sokal" criteria for similarity

Value

• a list with
• C
  Geary's C
• K
  sample kurtosis of x

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)))