From r-help Sun Jan 16 09:11:56 2005 From: Erik Norvelle Date: Sun, 16 Jan 2005 09:11:56 +0000 To: r-help Subject: Re: [R] graphing of Princomp object Message-Id: X-MARC-Message: https://marc.info/?l=r-help&m=110587185018301 Tobias, Great, works like a charm! I'm already seeing all kinds of patterns that were invisible before. I appreciate your help. -Erik On 15/01/2005, at 16:30, Tobias Verbeke wrote: > On Sat, 15 Jan 2005 15:53:18 +0100 > List account wrote: > >> Thanks, Tobias for the response. >> >> I tried the suggestion you gave, and apparently (at least according to >> the biplot manpage, only the first two members of the col vector are >> used, the first to plot the first set of values, i.e. the scores, and >> the second color is used for the loadings (I think I have that right). >> At any rate, if I add the clause 'col = c(rep("red", 100), rep("blue", >> 17), rep("green", 62))' I just get a bunch of red points! :( > > You're right. I'm sorry I did not read ?biplot, but only checked it had > a col argument (Semel in anno licet insanire..). > Anyway, with PCA it is not a good idea to plot both variables and > cases on one single plot, because the temptation is too great to > interpret > proximities between variables and cases. You'd better plot two > different > graphs, one for the cases and one for the `circle of correlations'. > > For plotting the cases, you could make up your own plot using > something similar to this: > > library(MASS) # for eqscplot > F1 <- yourpca$score[,1] > F2 <- yourpca$score[,2] > eqscplot(F1, F2, pch = 20) > text(F1, F2, labels = names(F1), > col = c(rep("red", 100), > rep("blue", 17), > rep("green", 62)), > pos = 3) > > > Tobias > >> Si vales, valeo... >> >> -Erik > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html