<H2>DESCRIPTION</H2>

A rhumbline is a line following a constant angle of the
compass (i.e., a line of constant direction).  There are 32
points on the compass (points are roughly 11 degrees 15
minutes apart).  <EM>d.rhumbline</EM> 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.

<P>

The user can run this program either interactively or
non-interactively.  If the user simply types
<B>d.rhumbline</B> on the command line without specifying
parameter values, the mouse will be activated and the user
will be asked to use the mouse to indicate the two
endpoints of the rhumbline.  The rhumbline is then drawn in
the default color (white). The program also outputs the
coordinate locations of the two endpoints on the user's
terminal and the number associated with the mouse button
depressed by the user in a format useful for input to other
programs.

<P>

Alternately, the user can 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.

<H2>NOTES</H2>

This program works only with longitude-latitude data bases. 

<H2>SEE ALSO</H2>

<EM><A HREF="d.geodesic.html">d.geodesic</A></EM>

<H2>AUTHOR</H2>

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

<p><i>Last changed: $Date: 2003/04/11 15:16:04 $</i>