[Proj] Distance calculations

Hamish hamish_b at yahoo.com
Fri Oct 17 02:08:01 PDT 2008


OvV_HN wrote:
> Let's throw in Saito.
....
> Tsutomu Saito, The computation of long geodesics on the ellipsoid through 
> Gaussian quadrature, Bull. Geod. 53 (1979), pp. 165-177


As long as we are throwing things in, I might as well point to the code
that GRASS is currently using:

http://trac.osgeo.org/grass/browser/grass/trunk/lib/gis/geodist.c
http://trac.osgeo.org/grass/browser/grass/trunk/lib/gis/geodesic.c

 Distance from point to point along a geodesic code from Paul
 D. Thomas, 1970 "Spheroidal Geodesics, Reference Systems, and
 Local Geometry" U.S. Naval Oceanographic Office, p. 162
 Engineering Library 526.3 T36s
http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0703541


at least that one is easy to test :)
https://trac.osgeo.org/grass/browser/grass/trunk/swig/python/examples/m.distance


I am wondering if someone did set up a horse race between all these
various solutions, what would be the criteria to judge them on?
-computational time and difference from the "gold standard"?


Hamish


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