[Proj] Problems with Pittman geodesic??
Gerald I. Evenden
geraldi.evenden at gmail.com
Sun Jan 18 20:57:33 EST 2009
While checking out the accuracy of Vincenty vs. Pittman
I was fairly consistently getting agreement to micron or
better.
BUT not always!!!
I would appreciate anyone who has a Pittman geodesic routine
to test the following inverse (WGS84 ellipsoid):
point 1 at 0 lat, 0 lon and point 2 at 45N 90E.
With my version of Pittman I get a distance of 9993541.5348708
AND I get the same distance while changing the longitude of the
second point from about 89.6 to a hair over 90.
At 0,0/45,89.5:
Pittman: 9970963.0100082
Vincenty:9970963.01000801
At 0,0/45,89.6
Pittman: 9993541.5348708
Vincenty:9978847.65947167
Pittman remained constant in this longitude interval
At 0,0/45,90
Pittman: 9993541.5348708
Vincenty:10010386.3610382
Between 90.0000001 and 90.000001 Pittman finally came back
into near agreement with Vincenty.
Note: I did nothing to the Pittman FORTRAN loaned from Mugnier
other than compile it with gfortran and link to a C driver.
--
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist
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