I didn't quite follow what the problem was. Does my calculator suffer
the same problem? It is also based on Vicenty.
http://williams.best.vwh.net/gccalc.htm
"Vic Fraenckel" <vfraenc1@nycap.rr.com> wrote in message news:<Wjj1b.1771$lk1.1472@twister.nyroc.rr.com>...
> I have implimented Vincenty's Direct and Inverse algorithms with both VB6
> and Delphi7. I have been distributing the code as open source.
>
> A user has pointed out a problem in the Inverse function which I had not
> noticed. The problem exists in both the VB6 and Delphi versions. I have
> been trying for several days to fix it. The essence of the problem is:
>
> given that point 1 is at a fixed latitude/longitude (I have been using
> 89N/0E) and compute a the length of a geodesic at say 20N/0E the length is
> 1,572,913.307 meters and when doing the same for 20S/0E (trans-equatorial)
> the length is the same. Obviously this is not correct. I believe the length
> of 89N/0 to 20N/0 is correct. I am using WGS84.
>
> My algorithm is taken directly from Vincenty's paper as published in "Survey
> Review" XXII, 176, April 1975 entitled "Direct and Inverse Solutions of
> Geodesics on the Ellipsoid with Application of Nested Equations"
>
> I would like to correspond with anyone that might shed some light on the
> problem. I am confident that the equations faithfully follow those in the
> paper, because they yield good results for known test cases of data that do
> not violate the conditions set forth above.
>
> Any enlightenment will be appreciated.
>
> TIA
>
> Vic
> --
> __________________________________________________ ______
>
> Victor Fraenckel - The Windman vfraenc1@nycap.rr.com
> KC2GUI www.windsway.com
>
> Home of the WindReader Electronic Theodolite
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> - Winston [Leonard Spencer] Churchill (1874 - 1965)
>
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