[R] Question about spatial statistics

[Roger Bivand]

On Tue, 10 Sep 2002, washington santos da silva wrote:

> I´m tryng  to use the SPDEP package in my research in the field of
> population genetics. My data set
> has the following format:
> 
>  -  x and y : coordinates,
> -  Z: allelic frequency in  each loci (in a total of 8 locis) - this
> variable can assume the values  0 ; 0.5 or 1.
> 
>  The objective is to verify if there is a possible spatial
> autocorrelation structure of the allelic frequency in a population of
> natives trees (copaifera langsdorffii).
> I had some doubts about the package:
> 
> 1)  Is the package suitable to analyze this kind of data?
> 2)  Are the spatial autocorrelation tests in the package suitable for
> this analysis?
> 3)  If it is, what are the steps needed to carry out the Moran's I or
> others tests ?
> 
The package may or may not be what you need, depending on how you - as the 
person knowing the field data and the science - conceptualise the spatial 
process. I have code from Cliff & Ord 1981 for Moran's I for ordinal data 
(ordered factor) that I will include in the next release of the package, 
but - as in many spatial data analysis situations - you usually need to 
try several alternative approaches, of which mapping the data is often the 
key one.

> Any help will be welcome.
> Regards and
> Thank you very much.
> 
> João Marcos Louzada
> Federal University of Lavras - Brasil
> 
> 

-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand at nhh.no
and: Department of Geography and Regional Development, University of
Gdansk, al. Mar. J. Pilsudskiego 46, PL-81 378 Gdynia, Poland.

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