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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