sp.mantel.mc: Mantel-Hubert spatial general cross product statistic

Description

A permutation test for the spatial general cross product statistic with Moran ($C_{ij} = z_i z_j$), Geary ($C_{ij} = (z_i - z_j)^2$), and Sokal ($C_{ij} = |z_i - z_j|$) criteria, for $z_i = (x_i - \bar{x}) / \sigma_{x}$. plot.mc.sim is a helper function to plot the outcomes of the permutation test.

Usage

sp.mantel.mc(var, listw, nsim, type = "moran", zero.policy = FALSE,
 alternative = "greater", spChk=NULL)
plot.mc.sim(x, xlim, xlab, main, sub, ..., ptype="density")

Arguments

var

a numeric vector the same length as the neighbours list in listw

listw

a listw object created for example by nb2listw

nsim

number of permutations

type

"moran", "geary" or "sokal" criteria for similarity

zero.policy

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

alternative

a character string specifying the alternative hypothesis, must be one of "greater" (default), or "less".

spChk

should the data vector names be checked against the spatial objects for identity integrity, TRUE, or FALSE, default NULL to use get.spChkOption()

the object to be plotted

xlim

the range of the x axis

xlab

a title for the x axis

main

an overall title for the plot

sub

a sub title for the plot

ptype

either "density" or "hist"

...

further arguments passed through

Value

A list with class htest and mc.sim containing the following components:
statisticthe value of the observed Geary's C.
parameterthe rank of the observed Geary's C.
alternativea character string describing the alternative hypothesis.
methoda character string giving the method used.
data.namea character string giving the name(s) of the data, and the number of simulations.
p.valuethe pseudo p-value of the test.
resnsim simulated values of statistic, final value is observed statistic
estimatethe mean and variance of the simulated distribution.

References

Cliff, A. D., Ord, J. K. 1981 Spatial processes, Pion, p. 22-24, Haining, R. 1990 Spatial data analysis in the social and environmental sciences, Cambridge: Cambridge University Press, p. 230--1. The function has been checked against general matrix code posted to the r-help list by Ben Bolker on 1 May 2001; another mantel() function is in the vegan package.

Examples

Run this code

data(oldcol)
sim1 <- sp.mantel.mc(COL.OLD$CRIME, nb2listw(COL.nb),
 nsim=99, type="geary", alternative="less")
sim1
plot(sim1)
sp.mantel.mc(COL.OLD$CRIME, nb2listw(COL.nb), nsim=99,
 type="sokal", alternative="less")
sp.mantel.mc(COL.OLD$CRIME, nb2listw(COL.nb), nsim=99,
 type="moran")

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