.TH d.geodesic 1grass "" "GRASS 6.4.4" "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
.SH SYNOPSIS
\fBd.geodesic\fR
.br
\fBd.geodesic help\fR
.br
\fBd.geodesic\fR  [\fBcoor\fR=\fIlon1,lat1,lon2,lat2\fR]   [\fBlcolor\fR=\fIstring\fR]   [\fBtcolor\fR=\fIstring\fR]   [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR] 
.SS Parameters:
.IP "\fBcoor\fR=\fIlon1,lat1,lon2,lat2\fR" 4m
.br
Starting and ending coordinates
.IP "\fBlcolor\fR=\fIstring\fR" 4m
.br
Line color
.br
Options: \fIred,orange,yellow,green,blue,indigo,violet,white,black,gray,brown,magenta,aqua,grey,cyan,purple\fR
.br
Default: \fIblack\fR
.IP "\fBtcolor\fR=\fIstring\fR" 4m
.br
Text color or "none"
.PP
.SH DESCRIPTION
\fId.geodesic\fR 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. 
.SH OPTIONS
This program can be run either interactively or non-interactively. 
If the user types \fBd.geodesic\fR on the command line and runs it without other program 
parameters, the mouse will be activated; the user is asked to use 
the mouse to indicate the starting and ending points of each geodesic line 
to be drawn. The default line color (black) and text color (red) 
will be used. 
.PP
Alternately, the user can specify the starting and ending coordinates 
of the geodesic, line color, and text color on the command line, 
and run the program non-interactively. 
.PP
Once the user indicates the starting and ending coordinates 
of the geodesic, the line and its length (in miles) are displayed to 
the user's graphics monitor. If the text color is set to \fInone\fR,
the great circle distance is not displayed.
.SH EXAMPLE
\fC
.DS
.br
g.region vect=world_political \-p
.br
d.mon wx0
.br
d.vect world_political type=area
.br
d.geodesic coor=55:58W,33:18S,26:43E,60:37N lcolor=red tcolor=violet
.br
.DE
\fR
.PP
\fIGeodesic line (great circle line)\fR
.SH NOTES
This program works only with GRASS locations using a longitude/latitude 
coordinate system. 
.SH SEE ALSO
\fId.rhumbline\fR
.SH AUTHOR
Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
.PP
\fILast changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $\fR
.PP
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.PP
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