[Proj] Implementation of ECEF to geodetic coords (closed form solution)

[Karney, Charles]

> From: Gerald I. Evenden [geraldi.evenden at gmail.com]
> Data: Thursday, January 29, 2009 22:21
>
> On Thursday 29 January 2009 22:14:53 Charles Karney wrote:
>
> > However, I have extended the method to ensure that it works close to
> > the center of the ellipsoid.  I believe that the accuracy is close
> > to the round-off limit for all inputs.
>
> What do you mean by "close to the center of the ellipsoid"?

    sqrt(x^2 + y^2 + z^2) <= a * e^2 / sqrt(1 - e^2)

(Vermeille's method breaks down in this sphere.)  This includes the
singularily of the transformation which is on the circle

    z = 0
    sqrt(x^2 + y^2) = a * e^2

--
Charles Karney <ckarney at sarnoff.com>
Sarnoff Corporation, Princeton, NJ 08543-5300

URL: http://charles.karney.info
Tel: +1 609 734 2312
Fax: +1 609 734 2662