[OSRS-PROJ] Re: Concerning calumny and the ellipsoidaltransverse Mercator

Gerald I. Evenden gerald.evenden at verizon.net
Sun Aug 24 12:47:06 EDT 2003

On Sun, 2003-08-24 at 11:45, Clifford J Mugnier wrote:
> I gave a one-day seminar at the ESRI Annual Convention this past July on
> Grids and Datums.  Ms. Melita Kennedy, the staff Geodesist at ESRI,
> informed me that they have developed an iterative Transverse Mercator
> direct and inverse that will be implemented soon in ESRI projection
> engines.  She said it will do ±90º from the central meridian.  Ms. Kennedy
> acknowledged that it was based on an obscure NOAA publication (Not NGS)
> published about 15 years ago in the form of a "C" program.

>From our continued boxing off group Strebe made the following

    "Jeff Dozier, "Improved Algorithm for Calculation of UTM and
    Geodetic Coordinates", NOAA Technical Reprot NESS 81"

Seems to fit Kennedy's statement.

> Breast beating and teeth gnashing aside, there are practical applications
> to using the Transverse Mercator in greater expansions from the central
> meridian than 3º for LARGE Scale topographic mapping, and there are a
> number of practical applications for ellipsoidal loxodromes in geodetic
> computations and LARGE scale mapping.

I recall that the UTM limit was spec'd at 3½° limit.  But it will go
to a larger extent without too much distortion.  Besides precision
needs drop off with smaller scale associated with larger extent.

I wonder why ESRI bothered as it seems to not be worth the effort
as an economic activity.  As you say, there's nothing the cadastral
world that has any use for it and it only confuses the issue.


> Just because something appears to be a "two-man" discussion does not mean
> that others do not watch the "tennis match."
> Cliff Mugnier
Gerald I. Evenden <gerald.evenden at verizon.net>

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