[R] Plotting Discriminants from qda

David Winsemius dwinsemius at comcast.net
Thu Feb 21 01:36:41 CET 2013

On Feb 20, 2013, at 2:42 PM, Melanie Zoelck wrote:

> Dear R Help Members,
> I am aware how to plot the LD1 vs LD2 from a lda in R, using the code:
> plot(baseline.systat.hat$x, col=baseline.systat.hat$class,pch=as.numeric(baseline.systat.hat$class))
> However, I need to use the quadratic discriminant function, qda due to data properties. Is there a way to obtain the same sort of plot for from a qda object (and the output of predict qda). I have not been able to find this and am a bit stumped. I cannot seem to find any information on plotting this.

Code for plotting qda results appears on p340 of MASSe4. However the comment that "Function predplot is given in the scripts" is not something I was able turn into anything useful after looking in hte index, searching the MASS website. Searching with Google for 'ripley MASS predplot' I find an R help posting by Gavin Simpson in 2003 that pointed to the file ch11.R in the MASS library, but I find that in the meantime it has moved to ch12.R in the "scripts" directory of ../library/MASS/


David Winsemius
Alameda, CA, USA

More information about the R-help mailing list