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Subject: Re: Haversine formulae for Great Circles
From: Chuck Taylor (ctaylor@XXX.XXX)
Date: Sun Nov 18 2001 - 13:08:13 EST
George Huxtable wrote:
> What an interesting contribution from Lu Abel! (copied below). Perhaps I
> can add something to it.
And you have, George. Thanks. One minor point. You wrote:
> Lu has pointed to a difficulty in the use of the standard great-circle
> distance formula. ...
>
> Even with this high
> accuracy, distances of 0.1 nautical miles have started to go a bit
> inaccurate, and distances which should be .01 miles are calculated as zero.
> With a computer using single-precision, things would be a lot worse. So the
> problem Lu has raised is a real one, in these special circumstances of
> close approach.
Why would one be interested in great circle routes for such short distances?
Mercator Sailing or Mid-Latitude Sailing would seem much more applicable for
distances under, say, 60 nautical miles.
Chuck Taylor
Everett, WA, USA
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