Date:         Tue, 5 Dec 2006 21:46:01 -0800
Reply-To:     David L Cassell <davidlcassell@MSN.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         David L Cassell <davidlcassell@MSN.COM>
Subject:      Re: test of spatial dependence??
In-Reply-To:  <96a6572d0612051337j10ed5e65veb01eecb84310d3c@mail.gmail.com>
Content-Type: text/plain; format=flowed

sasncsu@GMAIL.COM wrote:
>
>hello SAS-friends,
>
>I am a R beginner and try to ask a basic question:


If you are an R beginner, are you asking in the right place?
R has lots of spatial statistics capabilities, and a good mailing
list too.

That said, I'll stick to SAS here.

>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.

Do you have distances between fields, or {x,y} coordinates?
If you don't have some capability of constructing the distances,
then there's no way to know which fields are 'close' to each
other and which are far apart.  So there would be no way to
do this determination.

>PS, could someone confirm that "spatial dependence" is equivalent to
>"spatial correlation" or "spatial autocorrelation" or not.

It depends on who asked the question.  Really.  'spatial
dependence' is a really vague term.  What are you planning
on using the information for?  Modeling spatial correlations
in some manner of linear model?

>Thank you very much.
>XY
>
>
>--
>say hello to friends of STAT and GIS

Take a look at PROC VARIOGRAM to do the modeling of the
spatial structure.

HTH,
David
--
David L. Cassell
mathematical statistician
Design Pathways
3115 NW Norwood Pl.
Corvallis OR 97330

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