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Re: making a circle of certain values [message #56123 is a reply to message #56122]

Tue, 02 October 2007 08:43

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Loren Anderson writes:

> I'm not sure if this is what you need, but here are the guts of the
> tvcircle routine that David suggested:
>
> FUNCTION Circle, radius, xcenter, ycenter, NPoints=NPoints
> ; Returns the x and y values of a circle
>
> IF N_Elements(NPoints) EQ 0 THEN NPoints=100
>
> seeds = Findgen(npoints)/(npoints-1)*2*!pi
> xvals = sin(seeds)*radius+xcenter
> yvals = cos(seeds)*radius+ycenter
>
> RETURN, Transpose([[xvals], [yvals]])
> END

What is different about TVCIRCLE, however, is that it
*always* produces circles on a plot, as opposed to this
code, which might well produce ellipses if you have the
plot aspect ratio as something other than 1:1.

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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[Message index]

		Re: making a circle of certain values By: Craig Markwardt on Wed, 03 October 2007 01:42
		Re: making a circle of certain values By: David Fanning on Tue, 02 October 2007 09:33
		Re: making a circle of certain values By: Loren Anderson on Tue, 02 October 2007 09:30
		Re: making a circle of certain values By: David Fanning on Tue, 02 October 2007 08:43
		Re: making a circle of certain values By: Loren Anderson on Tue, 02 October 2007 08:24
		Re: making a circle of certain values By: Jean H. on Mon, 01 October 2007 13:21
		Re: making a circle of certain values By: David Fanning on Mon, 01 October 2007 13:09

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