[Proj] Global Gauss-Kruger and libproj4---the final story
Gerald I. Evenden
geraldi.evenden at gmail.com
Wed Aug 27 11:45:53 EDT 2008
Thanks to a reader I have a copy of the Lee-Thompson material for the
Transverse Mercator projection.
After perusing the material it is clear that no bivariate function operation
such as libproj4 can handle the general case of the global extent of the
Gauss-Kruger projection. This is because of the nature of the equator
graticule line and the fact that it branches into two parts as it approaches
90 degrees from the central meridian. That is, all points with 0 latitude
and with a delta longitude near 90 degrees will have *two* resultant
Cartesian coordinates---one for the northern hemisphere and one for the
southern hemisphere. Proj_fwd returns only one Cartesian point.
I had a suspicion that this was the case from viewing the "tombstone"
illustrations of TM referenced many weeks ago but had to wait to learn the
details of what was tranpiring.
So case closed.
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
More information about the Proj