[Proj] C++ code for exact Transverse Mercator Projection

Gerald I. Evenden geraldi.evenden at gmail.com
Wed Sep 17 14:07:55 EDT 2008

On Wednesday 17 September 2008 8:35:09 am Charles Karney wrote:
> Gerald I. Evenden wrote:
> > On Tuesday 16 September 2008 5:51:06 pm Charles Karney wrote:
> >> This is just a straightforward implementation of transformations
> >> given by Lee in his 1976 monograph.  The resulting code is quite
> >> fast.  I haven't done detailing timing on it.  However I estimate
> >> that it's no more than a "few" times slower than a standard series
> >> solution (a la Krueger).

I think a clarification is needed and, indeed, part of the problem is mine.  
When I speak of the Krüger solution I am referring to the Taylor series as 
expressed by PD Thomas "Conformal Projections in Geodesy and Cartography 
(1952), p. 2-3, which form the basis for standard TM as used in UTM and other 
grid system applications and is what is implemented in libproj4.  In some 
cases, the series is truncated even further.  I have not seen the Krüger 
paper but assumed it was somewhat similar to Thomas and represented the same 
basic solution.  Perhaps we/i should refer to tmerc as the Thomas TM--- 
the 't' in tmerc is for Thomas.
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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