Sphere based calculations for geography don't appear to be faster?

[Greg Troxel]

Marco Boeringa <marco at boeringa.demon.nl> writes:

> I am not suggesting geographiclib is a bad choice. It may well be the
> fastest and most efficient implementation out there for doing geodesic
> calculations. It is just that the current PostGIS Help documentation
> clearly suggests that switching to sphere based calculations can
> improve performance at the obvious cost of some less accuracy. And of
> course it would be interesting to know if a true sphere based
> implementation could be faster, but maybe nobody bothered to implement
> one as it can be a special case of spheroidal, IDK?

In that case, the thing to fix might be the docs.