[CF-metadata] proposed UTM projection

[Rich Signell]

John Caron wrote:

> Theres 2 parts:
> 
> 1) Transverse Mercator doesnt specify the ellipsoidal parameters, 
> presuming i suppose a spherical earth. Im working with a dataset where 
> im told the ellipsoidal form is needed for accuracy..

There are projections, and there are spheroids.   You can use any 
projection with any spheroid.  UTM is now most commonly used with the 
WGS84 spheroid,  but has and can be used with any of them!   Look at any 
(decent) map and it will tell you both the projection and the datum 
(which implies a spheroid).

> 
> 2) The UTM zone specification is in wide use, and is a shorthand for all 
> the other TM parameters.
> 

Ok.  So how about we add an attribute that specifies the UTM zone 
instead of a whole new projection.

My $0.02, as usual.

-- 
Richard P. Signell           rsignell at usgs.gov
U.S. Geological Survey       Phone: (508) 457-2229
384 Woods Hole Road          Fax:   (508) 457-2310
Woods Hole, MA  02543-1598