The Spherical Covariance Model

Description

RMspheric is a stationary isotropic covariance model which is only valid up to dimension 3. The corresponding covariance function only depends on the distance r ≥ 0 between two points and is given by

C(r) = (1 - 1.5 r + 0.5 r^3) 1_{[0,1]}(r).

Usage

RMspheric(var, scale, Aniso, proj)

Arguments

Details

This covariance model is valid only for dimensions less than or equal to 3.

The covariance function has a finite range.

Value

RMspheric returns an object of class RMmodel.

Note

Although this model is valid on a sphere, do not mix up this model with valid models on a sphere; see spherical models for a list of the latter.

Author(s)

Martin Schlather, schlather@math.uni-mannheim.de, http://ms.math.uni-mannheim.de

References

Gelfand, A. E., Diggle, P., Fuentes, M. and Guttorp, P. (eds.) (2010) Handbook of Spatial Statistics. Boca Raton: Chapman & Hall/CRL.

See Also

RMmodel, RFsimulate, RFfit, spherical models.

Examples

RFoptions(seed=0) ## *ANY* simulation will have the random seed 0; set
##                   RFoptions(seed=NA) to make them all random again

model <- RMspheric()
x <- seq(0, 10, 0.02)
plot(model)
plot(RFsimulate(model, x=x))