d.geodesic - GRASS GIS manual

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; Options: meters, kilometers, feet, miles; Default: meters

DESCRIPTION
OPTIONS
EXAMPLE
NOTES
SEE ALSO
AUTHOR

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