Demo shell scripts for the conversion of geographical coordinates
(longitude and latitude) to Universal Transverse Mercator (UTM) coordinates


To run one of the demo listed below, type the name of the demo shell 
script on the commandline of a terminal window.

Demo shell scripts:
    Xsuutm       Example usage of suutm (X window display)
    PSsuutm      Example usage of suutm (PostScript plots)
    Utmconv      Four usage examples of utmconv 
                    (forward and inverse UTM transformation)

Relevant selfdocs:  suutm, utmconv, suazimuth


The UTM grid and the transformation algorithm:

The Universal Transverse Mercator (UTM) system is a world wide coordinate 
system defined between 80S and 84N. It divides the Earth into 60 six-degree 
zones. Zone number 1 has its central meridian at 177W (-177 degrees), and
numbers increase eastward. The central meridian of each zone is given by:
    lon0 = 6 * (zone - 1) - 180 + 3

Within each zone, an Easting of 500,000 m is assigned to its central meridian 
to avoid negative coordinates (false Easting). On the northern hemisphere, 
Northings start at 0 m at the equator and increase northward. On the southern 
hemisphere a false Northing of 10,000,000 m is applied, i.e. Northings start 
at 10,000,000 m at the equator and decrease southward. 
Letters are sometimes used to identify different zones of latitude. The 
letters C-M indicate zones on the southern and the letters N-X zones on the 
northern hemisphere.

By default, the programs suutm and utmconv uses the standard UTM system 
outlined above, but the user may specify his or her own central meridian 
and values for false Easting and Northing (general Transverse Mercator 
projection; see Example 4 in Utmconv.sh).

In both programs (suutm and utmconv) a reference ellipsoid may be specified
by its semimajor axis and its flattening, or one of the pre-defined ellipsoids
may be selected (default is WGS 1984). 
The projection algorithm is an approximate solution (power series expansion) 
adopted from similar functions in the Perl package "Geo-Coordinates-UTM-0.06" 
by G. Crookham (CPAN, March 2007).


References:

DMA (1989). The universal grids: Universal Transverse Mercator (UTM) and
    Universal Polar Stereographic (UPS). Technical Manual TM8358.2.
    Defense Mapping Agency, Fairfax, VA. (detailed description of UTM)

NIMA (2000). Department of Defense World Geodetic System 1984 - its definition
    and relationships with local geodetic systems. Technical Report TR8350.2. 
    National Imagery and Mapping Agency, Geodesy and Geophysics Department, 
    St. Louis, MO. 3rd edition. (reference ellipsoids)

J. P. Snyder (1987). Map Projections - A Working Manual. 
    U.S. Geological Survey Professional Paper 1395, 383 pages.
    U.S. Government Printing Office. (map projections)



Nils Maercklin
RISSC, University of Naples
Fondazione IDIS
Via Coroglio 156
80124 Napoli, Italy
