Spatial Covariance Functions — expcov • spatial

Spatial covariance functions for use with surf.gls.

Usage

expcov(r, d, alpha = 0, se = 1)
gaucov(r, d, alpha = 0, se = 1)
sphercov(r, d, alpha = 0, se = 1, D = 2)

Arguments

r: vector of distances at which to evaluate the covariance
d: range parameter
alpha: proportion of nugget effect
se: standard deviation at distance zero
D: dimension of spheres.

Value

vector of covariance values.

References

Ripley, B. D. (1981) Spatial Statistics. Wiley.

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

See also

Examples

data(topo, package="MASS")
topo.kr <- surf.ls(2, topo)
correlogram(topo.kr, 25)
d <- seq(0, 7, 0.1)
lines(d, expcov(d, 0.7))