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 12:29:50 +0100 (Tue, 08 Nov 2011) $
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