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Re: Algorithm for lat/lon searching [message #49792]

Fri, 18 August 2006 12:17

news.qwest.net
Messages: 137
Registered: September 2005

Senior Member

"JD Smith" <jdsmith@as.arizona.edu> wrote in message
news:pan.2006.08.18.17.54.28.887505@as.arizona.edu...
> On Fri, 18 Aug 2006 10:50:56 -0400, Paul van Delst wrote:
..
> Here's a simple notion:
>
> Why not develop a "whole earth grid" in whatever binning and projection is
> useful (an equal area projection comes to mind), run all your land points
> (only) through HIST_ND, store the resulting REVERSE_INDICES, and then, for
> a given lat/lon, look up its position in the multi-dimensional reverse
> index vector, and read out the emissivity data points.

That is a good solution, and one that I have employed in the past.
I would just point out that it gives a square of data (or in general
rectangle
in lat and lon), so some points along the diagonal are farther away than
others.
If you want to get a constant radius disk, you will have to calculate
distances
(perhaps something like what I suggested in my other post).

Having said that I doubt that it would make much of a difference, and I
would
go with the square grid approach.

Cheers,
bob

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[Message index]

		Re: Algorithm for lat/lon searching By: news.qwest.net on Fri, 18 August 2006 12:17
		Re: Algorithm for lat/lon searching By: JD Smith on Fri, 18 August 2006 10:54
		Re: Algorithm for lat/lon searching By: Gordon Sande on Fri, 18 August 2006 08:18
		Re: Algorithm for lat/lon searching By: Paul Van Delst[1] on Fri, 18 August 2006 14:26
		Re: Algorithm for lat/lon searching By: Paul Van Delst[1] on Fri, 18 August 2006 14:23

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