R help - Sep 2002 - Re: Biplot function of PCA

[was sent a wrong R-help address; manually resent by MM]
Hello
I'am using the 'biplot' and 'biplot.pincomp' functions of
the 'mva'
package for my studies.

The biplot represents both the observations and the variables of a
matrix of multivariate data on the same plot.

The observations are represented by their numbers (the line of the data
matrix), but I would need to change it.

I would like to have the possibility, to represent on a biplot, the
observations, by their name, or , by the group or the cluster they
belong.

For instance:
tab is a data.frame (4 variables x 52 obsevations)

pc.tab_princomp(tab,cor=TRUE)

biplot.princomp(pc.tab)

km_kmeans(tab,3,100)

cl_cutree(hclust(dist(tab)),k=3)

# I would like to obtain:

biplot.princomp(pc.tab, nomi=cl)

#or

biplot.princomp(pc.tab,nomi=km$cluster)

Like that I could see how the clusters are spread on the PCA.

So, my question is,

Shall I write myself this new function ?

Perhaps someone already done-it? But how could I know.

Thank you taking your time for my problem.

Best regards

Francois BOUCAYS
*************************
Assistant Hospitalier Universitaire
Facult? de Chirurgie Dentaire
Sciences Anatomiques (Sous-Section 58.03)
3, ch. des Mara?chers - 31062 Toulouse Cedex
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Laboratoire de Chirurgie Cephalo-Rachidienne Assist?e par Ordinateur
Directeur: Pr F. Boutault
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tel: 05.62.17.29.29 - fax: 05.61.25.47.19
port: 06.13.24.44.45 - emel: fboucays at wanadoo.fr
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On Mon, 9 Sep 2002, Fboucays wrote:
> I'am using the 'biplot' and 'biplot.pincomp' functions
of the 'mva'
> package for my studies.
>
> The biplot represents both the observations and the variables of a
> matrix of multivariate data on the same plot.
>
> The observations are represented by their numbers (the line of the data
> matrix), but I would need to change it.
Did you try example(biplot.princomp)?  It uses names!

The functions use names if and only if the data are named.  All you need to
do is to add the names to your data frame.
> I would like to have the possibility, to represent on a biplot, the
> observations, by their name, or , by the group or the cluster they
> belong.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595


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