param.defaults: Setting Default Values of Variogram Parameters

In georob: Robust Geostatistical Analysis of Spatial Data

Description

Helper functions to set sensible default values for anisotropy parameters and for controlling what variogram and anisotropy parameters should be estimated.

Usage

default.aniso(f1 = 1., f2 = 1., omega = 90., phi = 90., zeta = 0.)

default.fit.param(
  variance = TRUE, snugget = FALSE, nugget = TRUE, scale = TRUE,
  alpha = FALSE, beta = FALSE, delta = FALSE, gamma = FALSE,
  kappa = FALSE, lambda = FALSE, mu = FALSE, nu = FALSE)

default.fit.aniso(f1 = FALSE, f2 = FALSE, omega = FALSE,
  phi = FALSE, zeta = FALSE)

Arguments

variance	variance (sill σ^2) of the auto-correlated component of the Gaussian random field B(s).
snugget	variance (spatial nugget σ^2_n) of the seemingly spatially uncorrelated component of B(s) (micro-scale spatial variation; default value snugget = 0).
nugget	variance (nugget τ^2) of the independent errors ε(s).
scale	range parameter (α) of the variogram.
alpha, beta, delta, gamma, kappa, lambda, mu, nu	names of additional variogram parameters such as the smoothness parameter ν of the Whittle-Mat\'ern model (see RMmodel and param.names).
f1	positive ratio f_1 of lengths of second and first semi-principal axes of an ellipsoidal surface with constant semi-variance in R^3 (default f1 = 1).
f2	positive ratio f_2 of lengths of third and first semi-principal axes of the semi-variance ellipsoid (default f2 = 1).
omega	azimuth in degrees of the first semi-principal axis of the semi-variance ellipsoid (default omega = 90).
phi	90 degrees minus altitude of the first semi-principal axis of the semi-variance ellipsoid (default phi = 90).
zeta	angle in degrees between the second semi-principal axis and the direction of the line defined by the intersection between the x-y-plane and the plane orthogonal to the first semi-principal axis of the semi-variance ellipsoid through the origin (default zeta = 0).

Value

Either a named numeric with initial values of anisotropy parameters (default.aniso) or named logical vector, controlling what parameters should be estimated (default.fit.param,
default.fit.aniso).

Author(s)

Andreas Papritz [e-mail].

See Also

georobIntro for a description of the model and a brief summary of the algorithms;

georob for (robust) fitting of spatial linear models.

Examples

default.aniso(f1 = 0.5, omega = 45)
default.fit.param(scale=FALSE, alpha = TRUE)
default.fit.aniso(f1 = TRUE, omega = TRUE)

georob documentation built on June 4, 2021, 5:06 p.m.