[R] adding an ellipse to a PCA plot

[John Fox]

Dear Lukas,

You might try the dataEllipse() function in the car package.

I hope this helps,
 John

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of Lukas Baitsch
> Sent: June-06-11 10:33 AM
> To: r-help at r-project.org
> Subject: [R] adding an ellipse to a PCA plot
> 
> Hi,
> 
> I created a principal component plot using the first two principal
> components. I used the function princomp() to calculate the scores.
> now, I would like to superimpose an ellipse representing the center and
> the 95% confidence interval of a series of points in my plot (as to
> illustrate the grouping of my samples).
> 
> I looked at the ellipse() function in the ellipse package but can't get
> it to work. the princomp()-function gives me the scores of each point,
> so I can calculate the mean and the 95%-CI, but I can't integrate this
> into the ellipse()-function). Is there a better way of doing this or can
> someone help me figure out this function?
> 
> best regards,
> 
> Lukas
> 
> ______________________________________________
> R-help at 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.