Two On A Big Ocean The Story of the First Circumnavigation
of the Pacific Basin
in a Small Sailing Ship

      

Other Books by
Hal Roth
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Re: query

Subject: Re: query
From: Michael Wescott (wescott_mike@XXX.XXX)
Date: Wed Aug 21 2002 - 15:57:48 EDT

> If I am at lat1, long1, and go XXX nm at TC YYY, What is the exact
> formula from spherical trigonometry to get lat2, long2 ?

> It would be constant TC.

An exact formula conforming to one of the standard ellipsoids
requires some rather hairy integral calculus. For practical purposes,
a reasonable solution is to use "Mercator Sailing". See chapter 24
of the American Practical Navigator (a.k.a. Bowditch) on the web at
"http://pollux.nss.nima.mil/pubs/". This method uses meridional parts
(see "Table 6" and "Explanation of Navigational Tables" in the same pub). 

--
        Mike Wescott
        Wescott_Mike@XXX.XXX



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