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Re: matching coordinates [message #55075 is a reply to message #55071]

Sun, 29 July 2007 06:53

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

jradavenport@gmail.com writes:

> Hello, I'm a long time lurker of this group, and finally have a
> problem I can't solve efficiently enough! I have coordinates for stars
> (RA and DEC for us astronomers out there), from two sources. i.e.
> (x1,y1) and (x2,y2). These lists are huge, like 150k for one and
> 5million in the other (a lot of stars!). I need to find the matches
> from these catalogs within a tolerance. I've tried a few programs
> I've found online (close_match_radec for instance) and they have not
> given me results I believe (multiple matches and such). Here is some
> horrible code I wrote just now which solves the problem VERY slowly:

Here is an article that might help:

http://www.dfanning.com/code_tips/matchlists.html

For background, you might want to read the precursor
article, and one of my personal favorites:

http://www.dfanning.com/code_tips/slowloops.html

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: matching coordinates By: JD Smith on Mon, 30 July 2007 17:20
		Re: matching coordinates By: Conor on Mon, 30 July 2007 07:58
		Re: matching coordinates By: jradavenport on Mon, 30 July 2007 04:12
		Re: matching coordinates By: jradavenport on Mon, 30 July 2007 03:36
		Re: matching coordinates By: Anthony[1] on Mon, 30 July 2007 00:41
		Re: matching coordinates By: Anthony[1] on Mon, 30 July 2007 00:41
		Re: matching coordinates By: David Fanning on Sun, 29 July 2007 06:53

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