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:
Alternately, the user can simply type:
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:
.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.
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
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 endOutput 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
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:
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.
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