### Re: Pseudo X/Y values, forward and reverse

Clifford J Mugnier <cjmce <at> lsu.edu>

2003-01-31 05:22:09 GMT

William,
Yes, it counts in BOTH directions. I'm currently writing the chapter on
"Object Space Coordinate Systems" for the new 5th edition of the "Manual of
Photogrammetry," and I'm including up to the 7th derivative in both direct
and inverse transformations. Why weren't greater expansions included into
PROJ4? It's not a topic of general interest in cartography. Cartographers
generally ignore such things, including the late John P. Snyder. John was
only interested in what was germain to the U.S. Geological Survey and the
scales of maps that they produced. John was never interested in geodetic
stuff. John avoided datums and such things.
WGS84 was a topic of vague interest at the time, NAD83 was just coming on
line, and cartographic interests were beginning to be getting into GIS
applications at the time. Remember now, that was 20 years ago! When it
came to private consulting stuff, John used my software (GRIDS 2.0)with the
full 15th derivative implementations in both direct and inverse for
transverse Mercator. USGS stuff was nice, but when it came to "real world"
applications, well ...
What's one of the rarest books ever printed? Try TM 5-241-10 "Universal
Transverse Mercator Grid EXTENSION OF ZONE TO ZONE TRANSFORMATION TABLES."
Sept, 1962, 642 pp.
No, I'm not going to fax a copy. Yes, it has the only copy (ever) of the
equations to the 15th derivative.
Conoco in Ponca City, OK., purchased a copy of my 7th derivative equations
of the Gauss-Krueger Transverse Mercator transformation back in 1988-1989.

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