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       ll2utm  -  Convert  latitude/longitude  geographical coordinates to UTM


       ll2utm [-L] | [latitude longitude [nad27 | nad83 | wgs84]]


       This program uses Redfearn’s formulas to convert a given  latitude  and
       longitude  into  the  equivalent  Universal  Transverse  Mercator (UTM)
       coordinates.  (This operation is often referred to as projection, since
       it  projects  a  curved surface onto a flat plane.)  The input latitude
       and longitude must be in  decimal  degrees.   Latitudes  south  of  the
       equator  are  negative,  and  longitudes west of the prime meridian are
       negative.  UTM is intended for use in the latitude range  from  80S  to
       84N.   The  program  will  accept input outside of this range, but will
       print a warning message.

       The output takes the form of a single  line,  containing  the  UTM  "x"
       value,  the  UTM "y" value, and the UTM zone, separated by white space.
       The "x" value includes the normal 500,000 false easting.  The "y" value
       includes  the  normal 10,000,000 false northing, if the point is in the
       southern hemisphere.  Points in the southern hemisphere are flagged  by
       making the zone number negative.

       If  you  provide  just  the  "-L"  option,  the program will print some
       license information and exit.

       Projections, and inverse projections, depend on defining  an  ellipsoid
       that  approximates the shape of the earth (the reference ellipsoid) and
       defining reference coordinates (the datum) that allow  measurements  to
       be  made.   Different  choices  of  the  ellipsoid  and datum can yield
       projections that differ by tens of meters.  There are a wide variety of
       choices,   due  to  both  the  historical  progression  of  measurement
       technology, and the desire to maximize accuracy  over  a  given  region
       (such as North America, or one of the United States).

       This program defaults to the North American Datum of 1927 (NAD-27) with
       the Clarke Ellipsoid of 1866, since these appear to be appropriate  for
       much  of  the  freely-available  data.   The data are apparently in the
       process of being  converted  to  the  Geodetic  Reference  System  1980
       (GRS-80)  ellipsoid  and NAD-83.  If you come across such data, you can
       specify "nad83" on the command line.  The GTOPO30 data  use  the  World
       Geodetic  System  1984  (WGS-84)  ellipsoid,  which  can  be invoked by
       specifying "wgs84" on the command line.


       The utm2ll(1) command provides the inverse conversion.

                                 Jul 24, 2001