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NAME
d.rhumbline - Displays the rhumbline joining two user-specified points, in the active frame on the user's graphics monitor.
KEYWORDS
display, distance
SYNOPSIS
d.rhumbline
d.rhumbline help
d.rhumbline [coor=lon1,lat1,lon2,lat2] [lcolor=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
DESCRIPTION
A rhumbline (loxodrome) is a line following a constant angle of the
compass (i.e., a line of constant direction). It crosses all meridians
at the same angle, i.e. a path of constant bearing.
d.rhumbline displays the
rhumbline joining any two user-specified points in the
active frame on the user's graphics monitor. The named
coordinate locations must fall within the boundaries of the
user's current geographic region.
The user can run this program either interactively or
non-interactively. If the user simply types
d.rhumbline on the command line and runs it without specifying
parameter values, the mouse will be activated and the user
will be asked to use the mouse to indicate the two
endpoints of the rhumbline. The rhumbline is then drawn in
the default color (black).
Alternately, the user can specify the starting and ending
longitude/latitude coordinates of the rhumbline and
(optionally) the color in which the rhumbline will be
displayed; in this case, the program will run
non-interactively.
EXAMPLE
g.region vect=world_political -p
d.mon x0
d.vect world_political type=area
d.grid 10
d.rhumbline coor=55:58W,33:18S,26:43E,60:37N lcolor=red
Rhumbline (loxodrome)
NOTES
This program works only with longitude-latitude locations.
SEE ALSO
d.geodesic
AUTHOR
Michael Shapiro,
U.S. Army Construction Engineering
Research Laboratory
Last changed: $Date: 2011-11-08 03:29:50 -0800 (Tue, 08 Nov 2011) $
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