NAME

m.region.ll - Converts Universal Transverse Mercator (UTM) coordinates falling within the current geographic region from UTM coordinates to geographic (latitude/longitude) coordinates.
(GRASS Data Import/Processing)

SYNOPSIS

m.region.ll
m.region.ll help
m.region.ll spheroid=name

DESCRIPTION

m.region.ll takes current geographic region settings in UTM coordinates, and converts them to geographic coordinates (i.e., latitudes and longitudes). It also prints the length (in meters) of one arc-second at each of the four edges of the geographic region. The user must enter the spheroid upon which to base the geographic coordinates.

The list of spheroids available is somewhat dynamic. It may not contain exactly the ones listed below. To determine the current list of possible spheroids, simply type in:

m.region.ll help
A list of available spheroids will be printed on the screen.

AVAILABLE SPHEROIDS

(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

m.region.ll spheroid=clark66
Results: 
WINDOW 4928000.00N 609000.00E ZONE 13
       4914000.00S 590000.00W

	 44.30.06N 44.29.57N
	103.52.04W 103.37.44W

	 44.22.32N 44.22.23N
	103.52.13W 103.37.55W

	At northern edge 1 arc-second longitude=22.088500m

	At southern edge 1 arc-second longitude=22.135998m

	At western edge 1 arc-second latitude=30.860285m

	At eastern edge 1 arc-second latitude=30.863082m
The values for the geographic coordinates are rounded to the nearest second in this example. They would be more precise in the actual output that is printed on the screen.

SEE ALSO

m.datum.shift
m.ll2u
m.u2ll
r.in.ll

AUTHOR

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

Last changed: $Date$