From: Alberto Monteiro <albmont_at_centroin.com.br>

Date: Mon 09 Oct 2006 - 19:52:34 GMT

R-help@stat.math.ethz.ch 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. Received on Tue Oct 10 05:54:01 2006

Date: Mon 09 Oct 2006 - 19:52:34 GMT

Kamila Naxerova wrote:

*>
*

> Is there a way to plot elliptical shapes? symbols()

*> only provides circles...
**>
*

Elipse centered at (x0, y0) with axes _a_ and _b_:

theta <- seq(0, 2 * pi, length=(big enough))
x <- x0 + a * cos(theta)

y <- y0 + b * sin(theta)

plot(x, y, type = "l")

Or, if you want to rotate it alpha degrees from the x-axis:

x <- x0 + a * cos(theta) * cos(alpha) - b * sin(theta) * sin(alpha) y <- y0 + a * cos(theta) * sin(alpha) + b * sin(theta) * cos(alpha)

Of course, the above formulas can be rewritten without the products of trig functions, but this way it's obvious what it's doing.

Alberto Monteiro

R-help@stat.math.ethz.ch 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. Received on Tue Oct 10 05:54:01 2006

Archive maintained by Robert King, hosted by
the discipline of
statistics at the
University of Newcastle,
Australia.

Archive generated by hypermail 2.1.8, at Mon 09 Oct 2006 - 20:30:29 GMT.

*
Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help.
Please read the posting
guide before posting to the list.
*