[Proj] Little geod problem

Karney, Charles charles.karney at sri.com
Fri Feb 25 10:38:10 EST 2011

I recommend the version of Geod that is included with GeographicLib,


Here's what it gives for this problem:

echo -12.4989444 130.88649687 -12.4989444 130.8864967 | Geod -i
-90.00000002 -89.99999998 0.018 0.018

The man page is available at


From: proj-bounces at lists.maptools.org [proj-bounces at lists.maptools.org] On Behalf Of Mikhail Tchernychev [misha at mail.geometrics.com]
Sent: Thursday, January 20, 2011 14:21
To: proj at lists.maptools.org
Subject: [Proj] Little geod problem

  Hello list,

I came across a small inconsistency in the geod program. What I use is:

geod +ellps=WGS84  -I -f "%.3lf" data_file

With data file:

-12.4989444 130.88649687 -12.4989444 130.8864967

What I got is:

-1.#IO  -1.#IO  -1.#IO

These two points are very close to each other however are not identical.
I would
not be surprised if geod would return 0 0 0. If fact this is what it
does if points
are simply identical.  I would suggest to round result to 0, even if it
is not but say
smaller than some reasonable number (0.01 m?)

  I hope this would help to improve great proj software even more.

Thank you,

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