[R-sig-Geo] Advice on GLS on residual variogram?

[ONKELINX, Thierry]

Hi Lyndon,

The results seems sensible to me. The difference in range and nugget
between the OLS variogram and the GLS correlation structure is IMHO not
a problem. They both are some the same magnitude. The GLS takes the
spatial structure directly into account. Hence the model fit
(parameters) will change and so will the residuals.

As far as a know, GLS uses an iterative algorithm to estimate the
correlation structure. That might explain the differences you observe
between the two machines. Rerunning the same model on the same dataset
and the same machine will also yield somewhat different results.

Best regards,

Thierry

------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek
team Biometrie & Kwaliteitszorg
Gaverstraat 4
9500 Geraardsbergen
Belgium

Research Institute for Nature and Forest
team Biometrics & Quality Assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium

tel. + 32 54/436 185
Thierry.Onkelinx at 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
  


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