Variogram.corSpatial function

Calculate Semi-variogram for a corSpatial Object

This method function calculates the semi-variogram values corresponding to the model defined in FUN, using the estimated coefficients corresponding to object, at the distances defined by distance.

## S3 method for class 'corSpatial'
Variogram(object, distance, sig2, length.out, FUN, ...)

Arguments

• object: an object inheriting from class "corSpatial", representing spatial correlation structure.

• distance: an optional numeric vector with the distances at which the semi-variogram is to be calculated. Defaults to NULL, in which case a sequence of length length.out

  between the minimum and maximum values of getCovariate(object) is used.

• sig2: an optional numeric value representing the process variance. Defaults to 1.

• length.out: an optional integer specifying the length of the sequence of distances to be used for calculating the semi-variogram, when distance = NULL. Defaults to 50.

• FUN: a function of two arguments, the distance and the range corresponding to object, specifying the semi-variogram model.

• ...: some methods for this generic require additional arguments. None are used in this method.

Returns

a data frame with columns variog and dist representing, respectively, the semi-variogram values and the corresponding distances. The returned value inherits from class Variogram.

References

Cressie, N.A.C. (1993), "Statistics for Spatial Data", J. Wiley & Sons.

Author(s)

José Pinheiro and Douglas Bates bates@stat.wisc.edu

See Also

corSpatial, Variogram, Variogram.default, Variogram.corExp, Variogram.corGaus, Variogram.corLin, Variogram.corRatio, Variogram.corSpher, plot.Variogram

Examples

cs1 <- corExp(3, form = ~ Time | Rat)
cs1 <- Initialize(cs1, BodyWeight)
Variogram(cs1, FUN = function(x, y) (1 - exp(-x/y)))[1:10,]