R: The Spherical Covariance Model

RMspheric {RandomFields} | R Documentation

## 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

`var,scale,Aniso,proj` | optional arguments; same meaning for any `RMmodel`. If not passed, the above covariance function remains unmodified.

### 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 temodel 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

### 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`, linkspherical 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))

[Package RandomFields version 3.1.50 Index]