NAME

       d.rhumbline  - Displays the rhumbline joining two longitude/latitude coordinates.

KEYWORDS

       display, distance, rhumbline

SYNOPSIS

       d.rhumbline
       d.rhumbline --help
       d.rhumbline  coordinates=lon1,lat1,lon2,lat2   [line_color=name]    [--help]   [--verbose]
       [--quiet]  [--ui]

   Flags:
       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       coordinates=lon1,lat1,lon2,lat2 [required]
           Starting and ending coordinates

       line_color=name
           Line color
           Either a standard color name or R:G:B triplet
           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 has to 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

       A geodesic line if shown over the political map of the world (demolocation dataset):
       g.region vector=country_boundaries -p
       d.mon wx0
       d.vect country_boundaries type=area
       d.rhumbline coordinates=55:58W,33:18S,26:43E,60:37N \
         line_color=yellow
       # show additionally 10 degree grid
       d.grid 10

       Rhumbline (loxodrome)

NOTES

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

SEE ALSO

        d.geodesic, d.grid

AUTHOR

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

       Last changed: $Date: 2014-12-19 22:55:37 +0100 (Fri, 19 Dec 2014) $

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       © 2003-2016 GRASS Development Team, GRASS GIS 7.0.3 Reference Manual