[R] Handling realisations in geoRglm

Ben Bolker bolker at zoo.ufl.edu
Wed Aug 30 15:23:47 CEST 2006


Chris Barker <cmbarker <at> ucdavis.edu> writes:

> 
However, after reading the packages' documentation and 
> searching the mailing lists and other sources, it seems that the 
> functions in geoRglm do not acknowledge the existence of multiple 
> realisations per site.  I see that the likfit() function in geoR has an 
> argument for realisations, but I cannot find anything similar in 
> geoRglm.  Is it possible to model data with repeated realisations from 
> the same sites using geoRglm?  If so, how can this be done and is there 
> a way to model dependence among the realisations over time?
> 
  I don't know; I would be interested in the conclusions you reach.
I, too, found the support for multiple realisations to be relatively
skimpy in geoR (only likfit, and not any of the variogram-based
methods, support realisations); the code for likfit.glsm in the
geoRglm packages also reveals no hint of realisation code.

  Even so, what there is in geoR says quite strongly that realisations
are expected to be independent.  My guess is that for complex space/time
dependence, and wanting an answer to a practical problem, you would be
better off with a GEE approach ...

Writing the package maintainer directly
would probably be more useful.

  Ben Bolker



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