Re: [R] [R-sig-Geo] Comparing spatial point patterns - Syrjala test

From: jiho <jo.irisson_at_gmail.com>
Date: Sun, 10 Feb 2008 08:20:32 +0100

On Feb 9, 2008 10:39 PM, milton ruser <milton.ruser_at_gmail.com> wrote:
> I have no idea of how to solve this issue, but I suggest you write to the
> authors of spatstat package. I think they could help you very much. Another
> thing is that there was a threhead on this many times ago. May be that Alan
> Swanson cold also help you.
>
> http://finzi.psych.upenn.edu/R/Rhelp02a/archive/51226.html

Thank you for your answer. Indeed I saw this email during my research before posting my message. Unfortunately nobody answered it. I just hoped that things may have improved in this area of R since then and that potential authors, such as authors of the spatstat package, would be reading these lists.
I will contact those people personally indeed.

Thanks again.

> > At several stations distributed regularly in space[1], we sampled
> > repeatedly (4 times) the abundance of organisms and measured
> > environmental parameters. I now want to compare the spatial
> > distribution of various species (and test wether they differ or not),
> > or to compare the distribution of a particular organism with the
> > distribution of some environmental variable.
> > Syrjala's test[2] seems to be appropriate for such comparisons. The
> > hamming distance is also used (but it is not associated with a test).
> > However, as far as I understand it, Syrjala's test only compares the
> > distribution gathered during one sampling event, while I have four
> > successive repeats and:
> > - I am interested in comparing if, on average, the distributions are
> > the same
> > - I would prefer to keep the information regarding the variability of
> > the abundances in time, rather than just comparing the means, since
> > the abundances are quite variable.
> >
> > Therefore I have two questions for all the knowledgeable R users on
> > these lists:
> > - Is there a package in which Syrjala's test is implemented for R?
> > - Is there another way (a better way) to test for such differences?
> >
> > Thank you very much in advance for your help.
> >
> > [1] http://jo.irisson.free.fr/work/research_tetiaroa.html
> > [2] http://findarticles.com/p/articles/mi_m2120/is_n1_v77/ai_18066337/pg_7

-- 
Jean-Olivier Irisson
UMR 5244 CNRS-EPHE-UPVD, 52 av Paul Alduy, 66860 Perpignan Cedex, France
+336 21 05 19 90
http://jo.irisson.free.fr/work/

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Received on Sun 10 Feb 2008 - 07:28:50 GMT

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