[R] test of spatial dependence?? - ask an ecologist?

[Xu Yuan]

Thanks David and Milton for replies. No, I don't have the coordiates.
In other words, my data are not point data. But I think there is a way
to test of spatial dependence for areal data or lattice data. In this
case, the variable of interest is typically the average value of an
area instead of a point. Do you how to do this?

 Thank you.
 Xu

On 12/6/06, Milton Cezar Ribeiro <milton_ruser at yahoo.com.br> wrote:
>
> I never used it, but I beleave that it is a job for "mantel.rtest()" available on "ade4" package.
>
> In fact Farrar are right, you will neet the XY coordinates. Give a look at "Legendre & Legendre" text book.
>
> HTH,
>
> Miltinho
> Brazil
>
> David Farrar <dfarrar at newrvana.com> escreveu:
>
>
> In addition to the 25 numbers, I assume you have coordinates of each field.
> Otherwise, I don't understand what you are trying to do. I think ecologists like to use a test due to Mantel in this situation.
>
> The prefix "auto" means "self," of course, the idea being that measurements of the same variable under different conditions are correlated. I guess this would be a case of "autodependence." For correlation versus dependence, check your  intro stats book.
>
> de nada,
> X'X
>
> Farrar
>
>
> Xu Yuan wrote:
> hello R-friends,
>
> I am a R beginner and try to ask a basic question:
>
> How to test the spatial dependence of a column of data? for example, I have
> 25 agricultural fields, and I measure the average slope (%) or pH for each
> field. All I have is 25 numbers.
>
> PS, could someone confirm that "spatial dependence" is equivalent to
> "spatial correlation" or "spatial autocorrelation" or not.
>
> Thank you very much.
> XY
>
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