On Feb 9, 2008 10:39 PM, milton ruser <[EMAIL PROTECTED]> 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/ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
