[Proj] geod C library?

Charles Karney charles.karney at sri.com
Tue Dec 4 10:01:06 EST 2012

On 2010-11-30 10:26, Evan Miller wrote:
> Hi all,
> I am looking for the functionality provided by "geod" and "invgeod"
> (great circle calculations) wrapped up in a plain C library. I found
> Charles Karney's Geographic Library, but that's C++.
> Does anyone know of such a library? Is there any reason (other than time
> and effort) that Proj.4 doesn't provide a geod API?
> Thanks,
> Evan Miller

The latest version of GeographicLib, 1.27, includes a straight C
implementation of the geodesic routines plus sample programs for solving
the direct and inverse geodesic problems.  Download the source
distribution from


and look in the legacy/C directory.  The API is documented at the
beginning of geodesic.h .

This version also includes Fortran, Python, Javascipt, and Matlab
implementations.  The Matlab implementation is also available from


and the Python implementation is also available from


Charles Karney <charles.karney at sri.com>
SRI International, Princeton, NJ 08543-5300

Tel: +1 609 734 2312
Fax: +1 609 734 2662

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