## NAME

m.u2ll - Converts Universal Transverse Mercator (UTM) coordinates to geographic (latitude/longitude) coordinates.
(GRASS Data Import/Processing Program)

## SYNOPSIS

m.u2ll
m.u2ll help
m.u2ll [-srwod] spheroid=name [zone=value] [input=name] [output=name]

## DESCRIPTION

m.u2ll converts Universal Transverse Mercator (UTM) northings and eastings to geographic coordinates (i.e., latitudes and longitudes). The user must specify the UTM coordinates to be converted and the spheroid on which the geographic coordinates will be based. The program also needs to know the UTM zone in which the input coordinates are located. However, if the user is running GRASS from a UTM data base LOCATION, m.u2ll will use this data base's UTM zone designation, if no zone is specified by the user.

The GRASS program m.ll2u performs the reverse operation, converting geographic coordinates to UTM coordinates.

The list of spheroids available is somewhat dynamic. At the time of this release, available spheroids included: airy, australian, bessel, clark66, everest, grs80, hayford, international, krasovsky, wgs66, wgs72, and wgs84 (see table below).

This command can be run either non-interactively or interactively. The user can run the program non-interactively by entering desired flag settings and parameter values on the command line using the following format:

  m.u2ll [-srwod] spheroid=name [zone=value] [input=name] [output=name]

Alternately, the user can simply type:

  m.u2ll

on the command line. In this case, the user will be prompted for parameter values and flag settings through the standard interface described in the manual entry for parser.

Input can be entered from the keyboard or from an input file. In either case, input should be entered with one UTM easting and northing pair per line, in the format shown below:

  easting northing easting northing easting northing easting northing . . end

.fi If the user sets the -r flag, m.u2ll will expect the order of the coordinates to be reversed, and stated as northing, easting pairs, rather than as easting, northing pairs. This is useful for passing ASCII GRASS vector (/dig) files, whose coordinates are stated as northing, easting pairs, directly through m.u2ll.

Similarly, the user can elect to send output to an output file or (by default) to standard output (the user's terminal screen). Example input and output are shown below (see EXAMPLE).

Program flag settings and parameters have the following meanings.

### Flags:

-s
  Specified UTM zone is in the southern hemisphere.
-r
  The order of coordinates is reversed in the input, and entered as: north east. This option allows the user to pass an ascii vector file through m.u2ll.
-w
  Do not flag invalid east, north input lines as errors.
-o
  Flag other invalid input lines as errors.
-d
  Output latitude/longitude values in decimal degrees, rather than in the form dd:mm:ss.

### Parameters:

spheroid=name
  Reference spheroid (ellipsoid).
  Options: airy, australian, bessel, clark66, everest, grs80, hayford, international, krasovsky, wgs66, wgs72, wgs84
zone=value
  UTM zone in which UTM coordinates are located.
  Options: 1-60
input=name
  Name of input file containing UTM values to be converted.
output=name
  Name to be assigned to output file containing longitude and latitude values.

AVAILABLE SPHEROIDS
(The on-line listing includes only the spheroid names.)

    (The on-line listing includes only the spheroid names.)      |
    Spheroid:      |   Semi-major axis   | Eccentricity sqrd (e),| Commonly used for:
                   | (Equatorial Radius) | Flattening (f),       |
                   |    (a):             | or Polar Radius (b):  |
    ---------------+---------------------+-----------------------+-------------
     airy          | a=6377563.396       | e=.006670540          |
     australian    | a=6378160           | f=1/298.25            | Australia
     bessel        | a=6377397.155       | e=.006674372          | Japan
     clark66       | a=6378206.4         | b=6356583.8           | N. America
     everest       | a=6377276.345       | e=.0066378466         | India, Burma
     grs80         | a=6378137           | f=1/298.257           |
     hayford       | a=6378388           | f=1/297               |
     international | a=6378388           | f=1/297               | Europe
     krasovsky     | a=6378245           | f=1/298.3             |
     wgs66         | a=6378145           | f=1/298.25            | worldwide coverage
     wgs72         | a=6378135           | f=1/298.26            | worldwide coverage
     wgs84         | a=6378137           | f=1/298.257223563     | worldwide coverage

## EXAMPLE

Assume the user has input the command:

  m.u2ll -s spheroid=wgs72 zone=4 input=utm.infile output=ll.outfile

where the input file utm.infile contains the following easting and northing UTM coordinate values and zone designations:

    	237740.85 2167292.10
    	238740.00 2167000.00
    	239000.00 2167100.00
    	237100.00 2166000.00
    	end

Output would then be sent to the output file ll.outfile, containing the below longitude and latitude coordinate values:

    	166:02:25.645137W   70:27:46.615528S
    	166:00:53.237056W   70:27:59.692673S
    	166:00:27.23258W    70:27:57.454281S
    	166:03:41.428895W   70:28:25.61617S
    	end

## NOTES

Users can add information to the ellipsoid parameter definition file on their systems (located in $GISBASE/etc/ellipse.table) to add spheroids not now among those supported by GRASS.

See m.ll2u for a brief discussion of spheroids.

The UTM zone designation determines on what area of the earth a point is found. The same UTM coordinates will be found in each different UTM zone. Look at the marginalia of your source map to determine into which UTM zone your UTM coordinates fall. Although the user can permissibly omit specification of a UTM zone when running this program under a UTM data base LOCATION, it is safer to specify it (see DESCRIPTION, above).

m.u2ll converts the first pair of coordinates on each line of input and leaves anything else on the line alone. If a line begins:

  xxxxxx.xx xxxxxxx.xx

then the xxxxxx.xx xxxxxxx.xx UTM coordinate pair is converted to a longitude, latitude pair. Any other information appearing on the line is left alone. If the line doesn't begin with a pair of coordinates in the above format, then the line is left as it is.

## FILES

See ellipsoid parameter definition file in $GISBASE/etc/ellipse.table.

## SEE ALSO

For australian, clark66, grs80, hayford, international, krasovsky, and wgs72 ellipsoid parameters, see:
John P. Snyder, Map Projections - A Working Manual, U.S. Government Printing Office, Washington DC, 1989. U.S. Geological Survey Professional Paper 1395; from Table 1, p.12.

For bessel, airy, everest, and wgs66 ellipsoid parameter values, see:
Thomas O. Seppelin, The Department of Defense World Geodetic System 1972, presented at the International Symposium on Problems Related to the Redefinition of North American Geodetic Networks, Fredericton, New Brunswick, Canada in May, 1974; see Table 9, p.35.

For wgs84 parameter values, see:
U.S. Naval Oceanographic Labs.

Also read GRASS User's Reference Manual entries for:
d.label
d.points
d.sites
d.where
m.datum.shift
m.gc2ll
m.ll2gc
m.ll2u
parser

## AUTHOR

Michael Shapiro, U.S.Army Construction Engineering Research Laboratory

Last changed: $Date: 2002/01/25 05:45:33 $