d.geodesic - Displays a geodesic line, tracing the shortest distance between two geographic points along a great circle, in a longitude/latitude data set.
d.geodesic [coor=lon1,lat1,lon2,lat2] [lcolor=string] [tcolor=string] [--verbose] [--quiet]
- Starting and ending coordinates
- Line color
- Options: red,orange,yellow,green,blue,indigo,violet,white,black,gray,brown,magenta,aqua,grey,cyan,purple
- Default: black
- Text color or "none"
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.
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.
g.region vect=world_political -p
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)
This program works only with GRASS locations using a longitude/latitude
Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
Last changed: $Date: 2011-11-08 03:23:06 -0800 (Tue, 08 Nov 2011) $
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