[Proj] Transverse Mercator algorithm

Charles Karney ckarney at sarnoff.com
Thu Sep 4 23:38:59 EDT 2008


Gerald I. Evenden wrote:
> On Thursday 04 September 2008 3:58:12 pm Charles Karney wrote:
>> Charles Karney wrote:
>>> It'll take a day or so to make my macsyma code for the exact transverse
>>> Mercator transformation presentable.
> 
> WARNING: anyone doing test with this script needs to know that the scale 
> factor is also set to 0.9996.  The ellipsoid was reference OK but not knowing 
> the scale factor had be set had me running around in circles for a minute.

Well, I did say the documentation was meager!  Use

   setparams(a,invf,k0)$

to set the major radius, inverse flattening, and central scale factor.
The default is

   setparams(6378137b0, 298.257223563b0, 0.9996b0)$

appropriate for UTM applications.  (But note that no false easting or
false northing is applied.)
-- 
Charles Karney <ckarney at sarnoff.com>
Sarnoff Corporation, Princeton, NJ 08543-5300

URL: http://charles.karney.info
Tel: +1 609 734 2312
Fax: +1 609 734 2662


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