[R-sig-ME] Cannot have zero distances in "corSpatial"

Thierry Onkelinx thierry@onkelinx @ending from inbo@be
Fri Dec 7 09:58:29 CET 2018

Dear Maia,

Add a correlation structure with nlme won't solve your problem. Is applies
the correlation structure on the residuals **within** each finest group as
defined by the random effects. The residuals **between** random effects
group are assumed to be independent. The spatial structure is your design
is probably defined by site and plot so this won't work.

Have a look at the INLA or inlabru packages. They can model spatially
correlated random effects. See
https://www.muscardinus.be/2018/07/inlabru-bru/ for some examples.

Best regards,

ir. Thierry Onkelinx
Statisticus / Statistician

Vlaamse Overheid / Government of Flanders
Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance
thierry.onkelinx using inbo.be
Havenlaan 88 bus 73, 1000 Brussel

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


Op do 6 dec. 2018 om 19:33 schreef Vinicius Maia <
vinicius.a.maia using hotmail.com>:

> Hi folks
> data structure: plots nested in sites, and observations nested in plots.
> both site and plots used as random factors
> When running a mixed model (lme4) I founded spatial autocorrelation on
> model residuals, thus, I tried nlme mixed models inclunding a spatial
> structure (e.g. corr=corExp(...)), since I have repeated measures at the
> same point (then, with the same coordinates) the package is unable to run,
> giving the error: Cannot have zero distances in "corSpatial" in nlme
> It seems to be a common and unsolved problem
> https://www.google.com/search?q=Cannot+have+zero+distances+in+%22corSpatial%22&ie=utf-8&oe=utf-8&client=firefox-b
> It is my first time here, sorry for any mistake in my post.
> Thanks
> vmaia
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