Hi! I'm doing a PCA on some testdata (only 2 features) currently to see what happens. I read a lot of times one should center ones data, so i left the option on.
But now i am scratching my head on how to correctly transform new data to be comparable to the data used in the pca. pca$x are the points (in PC system) the function returns origpoints%*%pca$rotation is not quite the same, because it is missing the centering for the original data i can of course do scale(origpoints,scaled=F) beforehand, and then the results will be the same, but for new data that option isn't available. So how would i properly transform it? greetings Jessica ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
