Spatial Covariance Functions

DESCRIPTION:

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)

REQUIRED ARGUMENTS:

r
vector of distances at which to evaluate the covariance
d
range parameter

OPTIONAL ARGUMENTS:

alpha
proportion of nugget effect
se
standard deviation at distance zero
D
dimension of spheres.

VALUE:

vector of covariance values.

SEE ALSO:

EXAMPLES:

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