Hi, I think that TWINSPAN and IndVal are not so different (well, it's true that you can use your own a-priori clustering method in IndVal, because its use is independent of the classification method), in fact, TWINSPAN is cited 38 times in Dufrene & Legendre 1997 IndVal paper. They largely discuss differences and limitations between both methods throughout their article,
cheers Andrés Jari Oksanen <jari.oksa...@oulu.fi> escribió: > On 13/04/11 15:34 PM, "Gavin Simpson" <gavin.simp...@ucl.ac.uk> wrote: > >> On Wed, 2011-04-13 at 09:25 -0300, Diogo B. Provete wrote: >>> Dear Zang, >>> this procedure is not currently used, since Pierre Legendre and coleagues >>> developed a new metric called IndVal, which is available in the labdsv >>> package in R. >> >> I'm sorry, (I don't like TWINSPAN...) but to claim TWINSPAN is not used >> because it has been superseded by the IndVal approach is totally >> incorrect. >> >> TWINSPAN and IndVal do **very** different things; the former produces a >> cluster analysis that happens to churn out [a form of] indicator species >> values, whilst the latter **only** computes [a form of] indicator values >> - you have to supply the clustering. >> > Howdy all, > > Gavin is absolutely correct here (and I am not a TWINSPAN fan either). > > Various clustering methods are the closest thing to Twinspan in base R. > However, they don't provide you species clustering which makes Twinspan > unique. Twinspan works on the original community matrix and produces a > simultaneous classification for plots and species. I don't use > classification but casually, and I don't know if there are such simultaneous > two-way classification problems in R. Indval and friends for quite a > different problem, like Gavin wrote (twice). > > As far as I know, Twinspan is not available in R. Two persons have contacted > me and proposed to port Twinspan to R, and I have provided them the basic > files and promised to help them in the work, but I haven't heard anything of > the project after the initial contact. > > I do think that Twinspan is a suboptimal choice for classification problems, > but I won't go into details. I urge you to study its behaviour yourself if > get your hands on Twinspan. > > Cheers, Jari Oksanen > > _______________________________________________ > R-sig-ecology mailing list > R-sig-ecology@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-ecology > -- Andrés Mellado Díaz Centre for Hydrological Studies CEH-CEDEX Water Quality Department Pº bajo de la Virgen del Puerto, 3 28005, Madrid SPAIN [[alternative HTML version deleted]]
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