.TH d.geodesic 1grass "" "GRASS 7.2.0" "Grass User's Manual"
.SH NAME
\fI\fBd.geodesic\fR\fR  \- Displays a geodesic line, tracing the shortest distance between two geographic points along a great circle, in a longitude/latitude data set.
.SH KEYWORDS
display, distance, great circle, shortest path
.SH SYNOPSIS
\fBd.geodesic\fR
.br
\fBd.geodesic \-\-help\fR
.br
\fBd.geodesic\fR \fBcoordinates\fR=\fIlon1,lat1,lon2,lat2\fR  [\fBline_color\fR=\fIname\fR]   [\fBtext_color\fR=\fIname\fR]   [\fBunits\fR=\fIstring\fR]   [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBcoordinates\fR=\fIlon1,lat1,lon2,lat2\fR \fB[required]\fR" 4m
.br
Starting and ending coordinates
.IP "\fBline_color\fR=\fIname\fR" 4m
.br
Line color
.br
Either a standard color name or R:G:B triplet
.br
Default: \fIblack\fR
.IP "\fBtext_color\fR=\fIname\fR" 4m
.br
Text color
.br
Either a standard color name or R:G:B triplet
.IP "\fBunits\fR=\fIstring\fR" 4m
.br
Units
.br
Units
.br
Options: \fImeters, kilometers, feet, miles\fR
.br
Default: \fImeters\fR
.SH DESCRIPTION
\fId.geodesic\fR displays a geodesic line in the active frame on the user\(cqs
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\(cqs current geographic region.
.SH OPTIONS
By default black line color and red text color will be used.
.PP
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 \fInone\fR,
the great circle distance is not displayed.
.SH EXAMPLE
A geodesic line if shown over the political map of the world
(demolocation dataset):
.br
.nf
\fC
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 \(rs
  line_color=yellow text_color=red units=kilometers
\fR
.fi
.PP
.br
\fIGeodesic line (great circle line)\fR
.SH NOTES
This program works only in GRASS locations with longitude/latitude
coordinate system.
.SH SEE ALSO
\fI
d.rhumbline,
d.grid,
m.measure
\fR
.SH AUTHOR
Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
.PP
\fILast changed: $Date: 2016\-12\-17 13:29:46 +0100 (Sat, 17 Dec 2016) $\fR
.SH SOURCE CODE
.PP
Available at: d.geodesic source code (history)
.PP
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.PP
© 2003\-2016
GRASS Development Team,
GRASS GIS 7.2.0 Reference Manual