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Re: Astronomys` Sixth Neighbour Needs Help [message #36019 is a reply to message #35884]

Mon, 11 August 2003 08:28

wmconnolley
Messages: 106
Registered: November 2000

Senior Member

I come across this sometimes. The basis of the solution is usually
something like:

> lon1=data.longitude & lon1(i)=-999
> lat1=data.latitude & lat1(i)=-999

> mindist=min(sqrt((lon1-lon1(i))^2+(lat1-lat1(i)^2),j)

That finds you the closest city (j), without using the inner loop, and
so is much faster. OK, it uses distance in lat-lon space: if you care about
the exact coordinates you can use convert_coord to get it in whatever
map projection you are using.

-W.

--
William M Connolley | wmc@bas.ac.uk | http://www.antarctica.ac.uk/met/wmc/
Climate Modeller, British Antarctic Survey | Disclaimer: I speak for myself
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[Message index]

		Astronomys` Sixth Neighbour Needs Help By: touser2001 on Thu, 24 July 2003 13:40
		Re: Astronomys` Sixth Neighbour Needs Help By: touser2001 on Tue, 29 July 2003 15:21
		Re: Astronomys` Sixth Neighbour Needs Help By: David Fanning on Tue, 29 July 2003 10:16
		Re: Astronomys` Sixth Neighbour Needs Help By: Pavel Romashkin on Tue, 29 July 2003 08:40
		Re: Astronomys` Sixth Neighbour Needs Help By: jjbezair on Tue, 29 July 2003 06:34
		Re: Astronomys` Sixth Neighbour Needs Help By: David Fanning on Mon, 28 July 2003 15:27
		Re: Astronomys` Sixth Neighbour Needs Help By: touser2001 on Mon, 28 July 2003 14:53
		Re: Astronomys` Sixth Neighbour Needs Help By: touser2001 on Mon, 28 July 2003 14:40
		Re: Astronomys` Sixth Neighbour Needs Help By: pford on Mon, 28 July 2003 11:30
		Re: Astronomys` Sixth Neighbour Needs Help By: David Fanning on Mon, 28 July 2003 08:32
		Re: Astronomys` Sixth Neighbour Needs Help By: David Fanning on Mon, 28 July 2003 06:45
		Re: Astronomys` Sixth Neighbour Needs Help By: Ben Panter on Mon, 28 July 2003 05:40
		Re: Astronomys` Sixth Neighbour Needs Help By: JD Smith on Sun, 27 July 2003 23:22
		Re: Astronomys` Sixth Neighbour Needs Help By: touser2001 on Sat, 26 July 2003 13:48
		Re: Astronomys` Sixth Neighbour Needs Help By: Ben Panter on Sat, 26 July 2003 00:48
		Re: Astronomys` Sixth Neighbour Needs Help By: touser2001 on Fri, 25 July 2003 19:14
		Re: Astronomys` Sixth Neighbour Needs Help By: Pavel Romashkin on Fri, 25 July 2003 15:34
		Re: Astronomys` Sixth Neighbour Needs Help By: wmconnolley on Mon, 11 August 2003 08:28
		Re: Astronomys` Sixth Neighbour Needs Help By: google_forums on Mon, 11 August 2003 14:20
		Re: Astronomys` Sixth Neighbour Needs Help By: google_forums on Mon, 11 August 2003 07:53
		Re: Astronomys` Sixth Neighbour Needs Help By: wmconnolley on Tue, 12 August 2003 09:57
		Re: Astronomys` Sixth Neighbour Needs Help By: google_forums on Tue, 12 August 2003 09:11
		Re: Astronomys` Sixth Neighbour Needs Help By: wmconnolley on Tue, 12 August 2003 01:40

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