[R-sig-ME] spatial correlation structure for GLS (nlme)
Thierry.ONKELINX at inbo.be
Fri Dec 10 13:18:45 CET 2010
Which residuals did you use? You need to normalised residuals because they take the effect of the correlation function into account.
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek
team Biometrie & Kwaliteitszorg
Research Institute for Nature and Forest
team Biometrics & Quality Assurance
tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be
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~ Sir Ronald Aylmer Fisher
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~ Roger Brinner
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> -----Oorspronkelijk bericht-----
> Van: r-sig-mixed-models-bounces at r-project.org
> [mailto:r-sig-mixed-models-bounces at r-project.org] Namens Ing.
> Agr." Agustín Alesso
> Verzonden: vrijdag 10 december 2010 12:38
> Aan: r-sig-mixed-models at r-project.org
> Onderwerp: [R-sig-ME] spatial correlation structure for GLS (nlme)
> I need some advice to include a spatial correlation structure
> to an ANOVA one-way GLS model.
> First, I fit a simple model asuming uncorrelated errors and
> plotted the residuals variogram which showed the spatial
> autocorrelation. Then, with gstat package, I fit some models
> to guess initial values for corSpatial.
> The best model fitted has a nugget efect with to spherical
> structures (2 ranges).
> Before adding more complexity to the model, I tried to fit
> few models with basic predefined corStructures and then
> looking at their residuals variograms. Although including
> correlation results in smaller AICs, the variograms still
> showing strong spatial correlation of residuals.
> Is there a way to bluid a spatial correlation structure
> including two ranges?
> Thanks in advance,
> Ing. Agr. Agustín Alesso
> Dpto. Ciencias del Ambiente
> Fac. Cs. Agrarias - UNL
> Kreder 2805 - S3080HOF - Esperanza
> Tel: 03496-428575 int 337/256
> R-sig-mixed-models at r-project.org mailing list
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