[R-sig-Geo] GSTAT: Zonal Anisotropy

[Edzer Pebesma]

On 12/06/2010 06:39 PM, Veronesi, Fabio wrote:
> 
> Suppose I have a dataset with a zonal anisotropy, by which there are two variogram models for two different directions.
> For assessing this anisotropy in GSTAT is it sufficient to use, in the kriging, a variogram model fitted with an alpha factor equal to the two directions?
> Many thanks,
> Fabio

Fabio, the alpha parameter value should be set to one of these two
directions, but the tol.hor parameter should be very small, close to
zero, to really obtain the information for this direction. This works,
in practice, only for regularly organized (e.g. gridded) data.

I would, in practice, always look at multiple directions to check
whether the data indeed reveal zonal anisotropy.

> 
> 
> Fabio Veronesi
> Ph.D Student
> Cranfield University
> 
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-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763  http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics      e.pebesma at wwu.de