NAME

       d.geodesic  - Displays a geodesic line, tracing the shortest distance between two geographic points along
       a great circle, in a longitude/latitude data set.

KEYWORDS

       display, distance

SYNOPSIS

       d.geodesic
       d.geodesic help
       d.geodesic  [coor=lon1,lat1,lon2,lat2]   [lcolor=string]   [tcolor=string]   [--verbose]  [--quiet]

   Parameters:
       coor=lon1,lat1,lon2,lat2
           Starting and ending coordinates

       lcolor=string
           Line color
           Options:
           red,orange,yellow,green,blue,indigo,violet,white,black,gray,brown,magenta,aqua,grey,cyan,purple
           Default: black

       tcolor=string
           Text color or "none"

DESCRIPTION

       d.geodesic  displays  a  geodesic  line  in the active frame on the user's graphics monitor. This is also
       known as the great circle line and traces the shortest distance between two user-specified points on  the
       curved  surface of a longitude/latitude data set. The two coordinate locations named must fall within the
       boundaries of the user's current geographic region.

OPTIONS

       This program can be run either interactively or non-interactively.  If the user types d.geodesic  on  the
       command line and runs it without other program parameters, the mouse will be activated; the user is asked
       to  use  the  mouse  to  indicate  the  starting and ending points of each geodesic line to be drawn. The
       default line color (black) and text color (red) will be used.

       Alternately, the user can specify the starting and ending coordinates of the geodesic,  line  color,  and
       text color on the command line, and run the program non-interactively.

       Once  the user indicates the starting and ending coordinates of the geodesic, the line and its length (in
       miles) are displayed to the user's graphics monitor. If the text color is set to none, the  great  circle
       distance is not displayed.

EXAMPLE

       g.region vect=world_political -p
       d.mon wx0
       d.vect world_political type=area
       d.geodesic coor=55:58W,33:18S,26:43E,60:37N lcolor=red tcolor=violet

       Geodesic line (great circle line)

NOTES

       This program works only with GRASS locations using a longitude/latitude coordinate system.

SEE ALSO

       d.rhumbline

AUTHOR

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

       Last changed: $Date: 2011-11-08 03:29:50 -0800 (Tue, 08 Nov 2011) $

       Full index

       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                   d.geodesic(1grass)