From: Barry Rowlingson <B.Rowlingson_at_lancaster.ac.uk>

Date: Fri 19 Aug 2005 - 01:31:22 EST

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 Received on Fri Aug 19 01:35:38 2005

Date: Fri 19 Aug 2005 - 01:31:22 EST

Romain Francois wrote:

> Why don't you want to use any specific library ? You can't reinvent the > wheel !!

True, but Madonna is always reinventing herself...

> There is a package ellipse on CRAN which will do what you are looking for. > Have you tried > > RSiteSearch("ellipse")

its simple geometry really:

* > theta=seq(0,2*pi,len=100)
** > e=1.5
** > r=3
** > x=e*r*cos(theta)
*

> y=r*sin(theta)

> plot(x,y,asp=1)

rotate with:

* > phi=pi/4
** > xr=x*sin(phi)+y*cos(phi)
*

> yr=-x*cos(phi)+y*sin(phi)

> plot(xr,yr,asp=1)

or something. Wrap that up into a function and you're done. This is off-the-cuff, I've probably messed something up. So use one prepared earlier from a library...

Baz

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 Received on Fri Aug 19 01:35:38 2005

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