spdep (version 0.1-6)

sp.correlogram: Spatial correlogram

Description

Spatial correlograms for Moran's I and the autocorrelation coefficient, with print and plot helper functions.

Usage

sp.correlogram(neighbours, var, order = 1, method = "corr", style = "W", 
  zero.policy = FALSE)
plot.spcor(x, main, ylab, ylim, ...)
print.spcor(x, ...)

Arguments

neighbours

an object of class nb

var

a numeric vector

order

maximum lag order

method

"corr" for correlation, "I" for Moran's I

style

style can take values W, B, C, and S

zero.policy

If FALSE stop with error for any empty neighbour sets, if TRUE permit the weights list to be formed with zero-length weights vectors

x

an object from sp.correlogram() of class spcor

main

an overall title for the plot

ylab

a title for the y axis

ylim

the y limits of the plot

...

further arguments passed through

Value

• returns a vector of coefficient values, with an attribute (cardnos) of tables of neighbour cardinalities for the lag orders used.

References

Cliff, A. D., Ord, J. K. 1981 Spatial processes, Pion, pp. 118--122, Martin, R. L., Oeppen, J. E. 1975 The identification of regional forecasting models using space-time correlation functions, Transactions of the Institute of British Geographers, 66, 95--118.

See Also

nblag, moran

Examples

data(nc.sids)
ft.SID74 <- sqrt(1000)*(sqrt(nc.sids$SID74/nc.sids$BIR74) +
  sqrt((nc.sids$SID74+1)/nc.sids$BIR74))
print(sp.correlogram(sidsorig.nb, ft.SID74*sqrt(nc.sids$BIR74), order=8,
  method="corr", zero.policy=TRUE))
print(sp.correlogram(sidsorig.nb, ft.SID74*sqrt(nc.sids$BIR74), order=8,
  method="I", zero.policy=TRUE))
plot(sp.correlogram(sidsorig.nb, ft.SID74*sqrt(nc.sids$BIR74), order=8,
  method="corr", zero.policy=TRUE))
drop.no.neighs <- !(1:length(sidsorig.nb) %in% which(card(sidsorig.nb) == 0))
sub.sidsorig.nb <- subset(sidsorig.nb, drop.no.neighs)
plot(sp.correlogram(sub.sidsorig.nb, subset(ft.SID74*sqrt(nc.sids$BIR74), 
  drop.no.neighs), order=8, method="corr"))