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))