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.oksanen@oulu.fi> escribió:

> On 13/04/11 15:34 PM, "Gavin Simpson" <gavin.simpson@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 because it has been superseded by the IndVal approach is totally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
>
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-- 
Andrés Mellado Díaz

Centre for Hydrological Studies CEH-CEDEX
Water Quality Department
Pº bajo de la Virgen del Puerto, 3
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