R help - May 2011 - ordiellipse

Hi Users,

I am trying to plot 95% confidence ellipses around the 4 groupings found in
a PCA ordination and identified a-priori by clustering. I am using
ordiellipse to plot the ellipses and it works fine except one of my groups
contains only 2 sites and I cannot get an ellipse around them. I'm assuming
that 2 points is not enough to perform the relevant calculations here,
however I would like to plot one if I could, if only for the sake of
pictorial consistency.

Andy

-- 
Andrew Halford Ph.D
Associate Research Scientist
Marine Laboratory
University of Guam
Ph: +1 671 734 2948

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On May 26, 2011 Andrew Halford wrote:
> I am using ordiellipse to plot the ellipses and it works fine except one
> of my groups 
> contains only 2 sites and I cannot get an ellipse around them. I'm
> assuming 
> that 2 points is not enough to perform the relevant calculations here, 
> however I would like to plot one if I could, if only for the sake of 
> pictorial consistency.
Ouch! for the rod that is likely to come. Advice? Collect more data, for the
sake of pictorial consistency. And if you can't then you can't. What you
have are the (available) "facts."

Regards, Mark.

-----
Mark Difford (Ph.D.)
Research Associate
Botany Department
Nelson Mandela Metropolitan University
Port Elizabeth, South Africa
--
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