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You might contact Dr. David E. Wallis. He devised a much simpler method than Dozier's. I've implemented it for the full-ellipsoid. You can see a plot of an earth-like ellipsoid here:<BR>
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http://mapthematics.com/Projection%20Images/Cylindrical/Transverse%20Mercator.GIF<BR>
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The method works for arbitrary eccentricities. Contact me privately if you're interested. Since it is Dr. Wallis's invention, I'll put you in contact with him. <BR>
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Regards,<BR>
-- daan Strebe<BR>
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<BR>
In a message dated 6/13/06 12:03:39, ovv@hetnet.nl writes:<BR>
<BR>
<BR>
<BLOCKQUOTE CITE STYLE="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px" TYPE="CITE"></FONT><FONT COLOR="#000000" FACE="Palatino" FAMILY="SERIF" SIZE="2">> BTW: what did you use to get the "exact" values?<BR>
My own stuff.<BR>
I had a very hard time finding solid code. Several people are guarding the<BR>
principles as a secret and are deliberately vague. Or they are trying to get<BR>
solid money from it by selling software or books.<BR>
But I persevered in trying to get the Dozier show on the road.<BR>
You (mr. Evenden) already found one error in his code, but this error has to<BR>
be corrected in 3 places. It's the error of the elliptic parameter m, which<BR>
has to be the elliptic modulus k in 3 cases (tmfd, gk, tmid).<BR>
It appeared that the Dozier code - the complex Newton iteration - was<BR>
useless in some regions, especially large lon-lon0 and low latitudes. First<BR>
I used somewhat better elliptic functions from Cernlib. But, to more effect,<BR>
I concocted another iteration scheme based on TOMS algorithm 365, a very<BR>
slow downhill walkaround method, yet very powerful.<BR>
I checked my results with an on-line calculator from professor Schuhr, based<BR>
on the Klotz algorithms.<BR>
<http://gauss.fb1.fh-frankfurt.de/cgi-bin/cgi_gk><BR>
This calculator fails for difficult areas (very large lon-lon0, small lat).<BR>
So I can only 'proof' my results in the difficult areas by doing a complete<BR>
round-trip and getting nearly the original data back.<BR>
And yes, I do the lon-lon0=90 degrees too.<BR>
<BR>
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