gstat (version 0.9-11)

vgm: Generate, or Add to Variogram Model

Description

Generates a variogram model, or adds to an existing model. print.variogram.model prints the essence of a variogram model.

Usage

vgm(psill, model, range, nugget, add.to, anis, kappa = 0.5)
print.variogram.model(x, ...)

Arguments

psill

(partial) sill of the variogram model component

model

model type, e.g. "Exp", "Sph", "Gau", "Mat". Calling vgm() without a model argument returns the list with available models.

range

range of the variogram model component

kappa

smoothness parameter for the Matern class of variogram models

nugget

nugget component of the variogram (this basically adds a nugget compontent to the model)

add.to

a variogram model to which we want to add a component

anis

anisotropy parameters: see notes below

x

a variogram model to print

...

arguments that will be passed to print, e.g. digits (see examples)

Value

• an object of class variogram.model, which extends data.frame Called without a model argument returns a character list with available models.

See Also

show.vgms to view the available models, print.variogram.model, fit.variogram, variogram.line, variogram for the sample variogram.

Examples

vgm(10, "Exp", 300)
x <- vgm(10, "Exp", 300)
vgm(10, "Nug", 0)
vgm(10, "Exp", 300, 4.5)
vgm(10, "Mat", 300, 4.5, kappa = 0.7)
vgm( 5, "Exp", 300, add.to = vgm(5, "Exp", 60, nugget = 2.5))
vgm(10, "Exp", 300, anis = c(30, 0.5))
vgm(10, "Exp", 300, anis = c(30, 10, 0, 0.5, 0.3))
# Matern variogram model:
vgm(1, "Mat", 1, kappa=.3)
x <- vgm(0.39527463, "Sph", 953.8942, nugget = 0.06105141)
x
print(x, digits = 3);
# to see all components, do
print.data.frame(x)