geo (version 1.4-3)

variofit: Function that fits a model to a variogram.

Description

Function that fits a model to a variogram. The fitting occurs either automatically or interactively. The function is called after the function variogram which calculates the variogram to which the model is fitted. Currently only spherical model is supported. Later other models will be added.

Usage

variofit(vagram, model = 1, option = 2, interactivt = F, sill = 0)

Arguments

vagram

List with the calculated variogram. Components of the list are: \$dist mean distance of the interval. \$vario calculated value of the variogram. \$number number of datapoints in the interval. In nearly all cases vagram will be the output from the program variogram.

model

Type of model. Default is spherical. It is currently the only model supported.

option

Method to use in automatic fitting. Allowed values are 1,2,3 and 4. Default value is 2. For further information see below.

interactivt

If T the fitting is done interactively by plotting the variogram on the screen and asking the user to select sill, range and nugget by the locator function.

sill

Sill of the variogram, or: Limit of the variogram tending to infinity lag distances (wikipedia).

Value

A list with the following components. \$nugget : Estimated nugget effect \$sill : Estimated sill \$range : Estimated range \$dist : mean distance of the interval. \$vario : calculated value of the variogram. \$number : number of datapoints in the interval.

See Also

variogram, pointkriging.