Fitting a 3D anisotropic variogram

Hello,

anybody know a function to fit a theoretical 3D variogram model to the
experimental data?

I work with pollution data from boreholes samples of marine sediment.
Generally the model that best fits to the data is a nested variogram with
both geometric and zonal anisotropy, composed by:

- nugget effect
- spherical model with short range (< 1 m) along the z axis and very long
range (1000 km) along  x and y axis
- spherical model with very long range  (10^6 m) along the z axis and
medium range (< 1 km) along  x and y axis

In the past I used Isatis to visually adapt the range of the model to the
experimental variogram and automatically fit the sill.
Now I'm moving on open source software and I'm looking for a way to fit at
least the sill of the 3D variogram to the data.

I found that gstat allows to use the 3D variogram, but doesn't fit the
anisotropic ones, and geoR fit the anisotropic variogram but not the 3D
ones.

Anybody knows a way in R to build and fit a variogram as that described
above?

Thanks,
Carlo

Carlo Innocenti, PhD

ISPRA
Istituto Superiore per la Protezione e la Ricerca Ambientale
High Institute for Environmental Protection and Research

Via Vitaliano Brancati, 60
00144 Roma
Italy

phone: +39 06 5007 4639
email: carlo.innocenti at isprambiente.it

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