[postgis-users] Determine latitude/longitude of a point given initial latitude/longitude, bearing and distance on a spheroid.

Jose Carlos Martínez Llario jomarlla at cgf.upv.es
Mon Nov 8 14:49:27 PST 2010

```You are talking about the "First geodetic problem". This is a well know
problem and it is solved
using different iterative approach . GeoTools has an implementation of
this problem in java and all of the geodesic software has different
algorithm to solve it. You can google 'geodesic problem' to find more
information. Any book about basic geodesy or geometric geodesy would be
ok too.

http://en.wikipedia.org/wiki/Geodesy
http://www.ferris.edu/faculty/burtchr/sure452/notes/direct-inverse.pdf

With a little bit of time im sure you can find much better links in
internet.

hope it helps
cheers,
Jose

On 08/11/2010 23:21, Paul Ramsey wrote:
> There is code for this in the lwspheroid.c file in liblwgeom. Note it
> is GPL. It's not exposed in SQL at the moment, I didn't realize people
> would have that use case. So file a ticket to make azimuth/bearing
> translations on the spheroid available in SQL.
>
> P
>
> On Mon, Nov 8, 2010 at 11:52 PM, Luke Wilmen<lukewilmen at gmail.com>  wrote:
>> G'day all,
>> Long time reader, first time poster. Recently I have been developing a
>> project that is requiring a point to be translated along a great circle path
>> by a given distance (metres) and initial bearing. I have already implemented
>> functions that do this with normal spherical calculations based upon an
>> average radius for the Earth. These spherical calculations work fine when
>> you are close to the equator however the accuracy is outside the tolerances
>> for our project as you move further towards the poles (points drift by
>> upwards of 10m - 20m).
>> After pouring over the Internet and this mailing list I have been unable to
>> find any solution for achieving these calculations on a spheroid/ellipsoid
>> and am wondering if anyone else has had any success in this area or would be
>> able to offer some advice?
>> Regards,
>> Luke.
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>>
>>
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--
------------------------------
José Carlos Martínez Llario

Producción Cartográfica y SIG.
Dpto. Ingeniería Cartográfica.
Univ. Politécnica de Valencia.

E-mail: jomarlla at cgf.upv.es
Telf: 963877007 ext. 75599
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