[OSRS-PROJ] Re: Lambert Conformal Conic 1SP

[Gerald I. Evenden]

251 is a useful book and a dog-eared copy sit on my shelf.

I also found a suspicious coefficient for the expression for
x in Tmerc on page 96.  For eqn 289, and the first row of
the expression for the lamda^7 term, the 6th term reads
"3,262".  I believe the value should be "3,298".

This was found when comparing extended precision Gauss
quadrature integrations, Thomas's expanded coefficients and
various "standard" versions of Tmerc.

What was a very interesting part of this endeavor is that
numerical integration allowed me to empirically determine
the correct 4 digit number that, when used in the evaluation,
the comparison was exact to 15 digits.  Just changing the
"8" up or down 1 would significantly alter the comparison.

There was no way I would carry out a re-derivation!  Thomas
was a masochist.

On Sun, 2003-02-09 at 22:45, Clifford J Mugnier wrote:
> 
> It's USC&GS Special Publcation 251, dated 1952.  "Conformal Projection in
> Geodesy and Cartography."  No, he did not offer guidance on such.  He
> presented the math with proofs and gave a few brief statement on usage
> throughout the world as he could apparently find out about in the USC&GS
> Library.  It was quite limited in comparison to what Army Map Service had,
> but that was mainly classified at the time and AMS was busy with the EU50
> Datum adjustment.  It is rumored that Paul D. Thomas did the math and
> derivations on contract to AMS for the UTM.
> 
> Cliff Mugnier
> LOUISIANA STATE UNIVERSITY
> 
> I don't have Thomas 1952. Out of curiosity, did he tender recommendations
> for choice of standard parallels?
> 
> Regards,
> 
> daan Strebe
> Geocart author
> 
> 
> 
> 
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