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Re: CALCULATION OF AREA ON A SPHERE [message #19055 is a reply to message #19054]

Tue, 22 February 2000 00:00

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

Med Bennett <mbennett@indra.com> writes:

> This is an interesting problem and I was hoping that someone would have
> provided a slick answer by now. I started searching the Web and came up
> with the following. It seems as though you could triangulate your points
> and then use the theorem presented below:
> [ ... deleted ... ]

This was discussed a little bit in August 1999 (see "area enclosed by
a polygon on a sphere" on www.deja.com). The tricky part of course is
computing the correct angles. Struan Gray wondered if there was a
utility routine in the idlastro library which could help.

Try GCIRC of idlastro, but also these two from the "JHU/APL/S1R usr
Library".

SPHGC Find intersections of two great circles on sphere.
SPHIC Compute intersection points of two circles on a unit sphere.

I found these here:
http://www.astro.washington.edu/deutsch/idl/

Craig

P.S. A little research is all it takes!

--
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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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[Message index]

		Re: CALCULATION OF AREA ON A SPHERE By: Ben Tupper on Wed, 23 February 2000 00:00
		Re: CALCULATION OF AREA ON A SPHERE By: davidf on Tue, 22 February 2000 00:00
		Re: CALCULATION OF AREA ON A SPHERE By: Craig Markwardt on Tue, 22 February 2000 00:00
		Re: CALCULATION OF AREA ON A SPHERE By: Med Bennett on Tue, 22 February 2000 00:00
		Re: CALCULATION OF AREA ON A SPHERE By: Tim Cross on Thu, 24 February 2000 00:00
		Re: CALCULATION OF AREA ON A SPHERE By: Tim Cross on Mon, 28 February 2000 00:00
		Re: CALCULATION OF AREA ON A SPHERE By: Stein Vidar Hagfors H[1] on Mon, 28 February 2000 00:00
		Re: CALCULATION OF AREA ON A SPHERE By: James Kuyper on Thu, 23 March 2000 00:00

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