# [R] ploting an ellipse keeps giving errors

Sun sun at cae.wisc.edu
Wed Oct 27 11:25:00 CEST 2004

```Thank you. I found there are two ellipses

1.
R2.0
library (car)

2.
R1.9 and R2.0
library (ellipse)

And they are different! I can't run 1.

But the 2. is kind of specialized for t-distribution confidence and so on.

I need to find a general ellipse for an ellipse equation like
(x-x0)^2/a + (y-y0)^2/b =1

. Since I used chi-square percentile not t. I am trying to obtain the large
sample 95% simultaneous confidence ellipse for two population means (say,
weight and height). The input are the two sample means and their
covariances.

Maybe I have to make my own ellipse function.

Sun
----- Original Message -----
From: "Petr Pikal" <petr.pikal at precheza.cz>
To: "Sun" <sun at cae.wisc.edu>
Cc: <r-help at stat.math.ethz.ch>
Sent: Wednesday, October 27, 2004 4:14 AM
Subject: Re: [R] ploting an ellipse keeps giving errors

> Hi
>
> Did you read what ellipse does and how it shall be used?
>
>
> From your example i got
>
> > ellipse (center = c(0,0), shape = shape1, radius = 1)
> Error in ellipse.default(center = c(0, 0), shape = shape1, radius =
> 1) :
>         Argument "x" is missing, with no default
>
> Ellipse is not for drawing arbitrary ellipses but has different usage.
>
> See its help page and an example.
>
> Cheers
> Petr
>
>
>
>
> On 27 Oct 2004 at 3:34, Sun wrote:
>
> >
> > library (ellipse)
> >
> > shape1 = c (1, 0, 0,1)
> > dim(shape1) = c(2,2)
> > ellipse (center = c(0,0), shape = shape1, radius = 1)
> >
> > =============================
> > Error in plot.xy(xy.coords(x, y), type = type, col = col, lty = lty,
> > ...) :
> >         plot.new has not been called yet
> >
> >
> > It is really frustrating. Also what do the shape matrix, radius
> > correspond to an ellipse function
> >
> > (x-x0)^2/a + (y-y0)^2/b = 1
> >
> >
> > Many thanks,
> >
> > Sun
> >  [[alternative HTML version deleted]]
> >
> > ______________________________________________
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