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, great circle, shortest path

SYNOPSIS

       d.geodesic
       d.geodesic --help
       d.geodesic    coordinates=lon1,lat1,lon2,lat2     [line_color=name]      [text_color=name]
       [units=string]   [--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

       text_color=name
           Text color
           Either a standard color name or R:G:B triplet

       units=string
           Units
           Units
           Options: meters, kilometers, feet, miles
           Default: meters

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

       By default black line color and red text color will be used.

       By indicating the starting and ending coordinates of the geodesic, the line and its length
       (by default in meters) are displayed to the graphical output. If the text color is set  to
       none, the great circle distance is not displayed.

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
       # show additionally a 20 degree grid
       d.grid 20
       d.geodesic coordinates=55:58W,33:18S,26:43E,60:37N \
         line_color=yellow text_color=red units=kilometers

       Geodesic line (great circle line)

NOTES

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

SEE ALSO

        d.rhumbline, d.grid, m.measure

AUTHOR

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

       Last changed: $Date: 2016-12-17 13:21:05 +0100 (Sat, 17 Dec 2016) $

SOURCE CODE

       Available at: d.geodesic source code (history)

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       © 2003-2018 GRASS Development Team, GRASS GIS 7.4.0 Reference Manual