[Qgis-developer] QGIS API Distance, Azimuth/Bearing - API Documentation

Nyall Dawson nyall.dawson at gmail.com
Sun Apr 16 18:56:22 PDT 2017

On 14 April 2017 at 01:56, C Hamilton <adenaculture at gmail.com> wrote:
> Thanks for answering. Geographiclib has a good summary of the benefits over
> vincinty.
> https://geographiclib.sourceforge.io/html/python/geodesics.html
> The algorithms implemented by this package are given in Karney (2013) and
> are based on Bessel (1825) and Helmert (1880); the algorithm for areas is
> based on Danielsen (1989). These improve on the work of Vincenty (1975) in
> the following respects:
> The results are accurate to round-off for terrestrial ellipsoids (the error
> in the distance is less then 15 nanometers, compared to 0.1 mm for
> Vincenty).
> The solution of the inverse problem is always found. (Vincenty’s method
> fails to converge for nearly antipodal points.)
> The routines calculate differential and integral properties of a geodesic.
> This allows, for example, the area of a geodesic polygon to be computed.

There's also https://github.com/mapbox/cheap-ruler - potentially this
could be faster and more accurate then Vincenty for smaller distance


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