RandomFields (version 3.0.62)

RMspheric: 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 $r \ge 0$ between two points and is given by $$C(r) = \left(1 - \frac{3}{2} r + \frac{1}{2} r^3\right) 1_{[0,1]}(r)$$

Usage

RMspheric(var, scale, Aniso, proj)

Arguments

var,scale,Aniso,proj

optional arguments; same meaning for any RMmodel. If not passed, the above covariance function remains unmodified.

Value

• RMspheric returns an object of class RMmodel

Details

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

The covariance function has a finite range.

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, link{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, if (interactive()) 0.02 else 1) 
plot(model)
plot(RFsimulate(model, x=x))
FinalizeExample()