Re: Estimate of spatial error term
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Re: Estimate of spatial error term

> Dear all,
> I was wondering if anyone out there can show me on how to get an estimate
> of the spatial error term.  It seem to me that ASREML (.sln file) only give
> us the estimate of the combined error (the spatial error + random error).
> Any suggestions are welcome, thank you.
> Cheers,
> dadan
> Dadan Kusnandar
> Ph.D Student
> Agricultural and Resource Economics
> The University of Western Australia
> Nedlands, W.A 6907
> Ph.  +61 - 8 - 9380 3419
> Fax. +61 - 8 - 9380 1098
> E-mail:

Dear Dadan,

I presume you are considering the analysis of a single trial
where an AR x AR correlated arror model is fitted.

When there is a reasonable amount of spatial correlation, 
you can add '!r units' to the model in which case it will estimate
the uncorelated error and the Residual will estimate the correlated error.

Sometimes the 'units' component can not be estimated [especially when there
is not much correlated error].  

Another approach [which takes longer computationally] but which is otherwise
equivalent is to fit the error as independent effects and include
a row.col as a random factor. It would need to be spacified as

row.col 3
row 0 AR .1   # row autocorrelation
col 0 AR .1   # column autocorrelation
1 0 I .1      # gamma for correlated error component

I trust thuis helps,
Arthur Gilmour PhD                    email:
Senior Research Scientist (Biometrics)                 fax: <61> 2 6391 3899
NSW Agriculture                             telephone work: <61> 2 6391 3815
Orange Agricultural Institute                         home: <61> 2 6362 0046
Forest Rd, ORANGE, 2800, AUSTRALIA         

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