[R] biplot.princomp - changing score labels

[Axel Strauß]

Thanks for the hints! They seem to help me.

Axel

Héctor Villalobos schrieb:
> Perhaps this may help you.
>
> Regards
>
>
>
>
> data(iris3)
>
> ir <- rbind(iris3[ , , 1], iris3[ , , 2], iris3[ , , 3])
>     
>   ir.pca <- princomp(ir)
>   biplot(ir.pca)
>
> # Rehacer Biplot
> # Calcular Factor para re-escalar scores y eigenvectores
>   lambda <- ir.pca$sdev[1:2] * sqrt(ir.pca$n.obs)
>
>   scores <- t( t(ir.pca$scores[ , c(1, 2)]) / lambda 
> )                        
>   variables <- t( t(ir.pca$loadings[ , c(1, 2)]) * lambda )
>  
>      
>   x11()
>   plot(scores, type="p", xlim=c(-0.22, 0.24), ylim=c(-0.2, 0.2),
>   pch=c(rep(16, 50), rep(21, 50), rep(14, 50)),
>   col=c(rep("red", 50), rep("blue", 50), rep("green", 50)))
>     abline(v=0, h=0, lty=3)
>   par(new=TRUE)
>   plot(variables, type="n", xaxt="n", yaxt="n", xlim=c(-22, 24), 
> ylim=c(-20, 20))
>     arrows(0, 0, variables[ , 1], variables[ , 2], len=0.1, col="red")
>     text(2*variables, rownames(variables), col="red", xpd=TRUE)
>     axis(3); axis(4)
>
>
>
> On 25 Feb 2009 at 9:52, Axel Strauß wrote:
>
> Date sent:                  Wed, 25 Feb 2009 09:52:54 +0100
> From:                         Axel Strauß <a.strauss at tu-bs.de>
> To:                            R-help at r-project.org
> Subject:                     Re: [R] biplot.princomp - changing score 
> labels
>
> > Prof Brian Ripley schrieb:
> > > On Tue, 24 Feb 2009, Axel Strauß wrote:
> > >
> > >> OK, the one thing I figured out:
> > >> Is should be like:
> > >> biplot(test.pca, cex=c(2,1), col=c("red","green")...
> > >> to change size, colours etc separately. But I still don't know how
> > >> change lables of observations to symbols properly.
> > >
> > > That's not part of the design of the function, so just make a copy
> > > and edit to meet your fancies.
> > >
> > > The designer of biplot.princomp.
> > >
> > The idea behind my question was actually not a "styling one" but to
> > provide additional information in the graph. My observations have
> > different species richness and I wanted to adopt symbol size to the
> > number of species to show the change of species richness along the
> > PCs. Anyway, thanks for the comment - and for designing
> > biplot.princomp.
> >
> > Axel
> >
>
>
> -- 
> Héctor Villalobos <hvillalo at ipn.mx>
>  CICIMAR - IPN
>  A.P. 592. Col. Centro
>  La Paz, Baja California Sur, MÉXICO. 23000
>  Tels. (+52 612) 122 53 44; 123 46 58; 123 47 34  ext. 82425
>  Fax.  (+52 612) 122 53 22


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