[R] anisotropy in vgm model. HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[ONKELINX, Thierry]

Dear Alessandro,

For the vgm-helpfile:
"Anisotropy parameters define which direction this is (the main axis), and how much shorter the range is in (the) direction(s) perpendicular to this main axis."

Notice that the directions should be perpendicular. 90° and 45° are not perpendicular.

Please don't forget to provide commented, minimal, self-contained, reproducible code as the posting guide requests. In this case it was not reproducible because we don't have the dataset. Futhermore R-sig-geo would be a more a propriate mailing list for this kind of questions.

HTH,

Thierry


----------------------------------------------------------------------------
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium 
tel. + 32 54/436 185
Thierry.Onkelinx op inbo.be 
www.inbo.be 

To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of.
~ Sir Ronald Aylmer Fisher

The plural of anecdote is not data.
~ Roger Brinner

The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data.
~ John Tukey

-----Oorspronkelijk bericht-----
Van: r-help-bounces op r-project.org [mailto:r-help-bounces op r-project.org] Namens Alessandro
Verzonden: donderdag 31 juli 2008 23:23
Aan: r-help op r-project.org
Onderwerp: [R] anisotropy in vgm model. HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Hi All,



I have this problem. I don't understand  the right code in R when I have an
anisotropy in the semivariogram model



plot(variogram(Z~1, subground, cutoff=1800, width=80, alpha=c(45, 135, 90,
135)))



I have a good model in 90° and eventually in 90° and 45°



v = variogram(Z~1, subground, cutoff=1800, width=80, alpha=c(0, 45, 90,
135))

v.fit = fit.variogram(v, vgm(model="Lin", anis=c(?????????)))





Thank you



Alessandro


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