[Proj] Re: Transverse Mercator algorithm

[strebe]

Frank:

I reviewed a promising paper on this topic two years ago. The author took the novel approach of leaving the series development on the complex plane instead of teasing apart the real and imaginary portions. This resulted in a much simpler expression of the series, including inverse. This leaves room for more terms without becoming unwieldy. Unfortunately the paper came with some important problems and did not see publication in that form. I do not know who the author was, or authors were, and I have not heard any more about it. 

You might contact Elisabeth Nelson of CaGIS about manuscript MS06916, "The Formulation of Gauss Projection by Complex Numbers". It may be that the author has published by now, or that "he" would be willing to share details anyway.

Regards,
-- daan Strebe


On May 27, 2008, at 8:52:08 AM, "Frank Warmerdam" <warmerdam at pobox.com> wrote:
From:   "Frank Warmerdam" <warmerdam at pobox.com>
Subject:    Re: [Proj] Transverse Mercator algorithm
Date:   May 27, 2008 8:52:08 AM PDT
To: "PROJ.4 and general Projections Discussions" <proj at lists.maptools.org>
Oscar van Vlijmen wrote:
> In my opinion, there are 2 possibilities:
> 
> * High accuracy.
> * Speed.

Folks,

To state the obvious, computers are pretty fast now, so for many purposes
a TM variant that is quite a bit slower would be acceptable.

I would like to see a TM version that is very reversable well outside the
typical six degree swath around the central meridian.

Mostly I wish I could have a highly reversable TM variant that was exactly
the same as the existing TM approximation in at least one direction. It is
the failure to reverse that is a nightmare for me.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | President OSGeo, http://osgeo.org

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