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=back

=head1 METHODS

=over 4

=item plot_track(TRACK_ARRAY_REF, OUTPUT_FILE, OPTION_HASH_REF)

Creates a plot of the position track provided by the TRACK_ARRAY_REF 
and outputs it to the OUTPUT_FILE filename.  The plot configuration
options are contained in the OPTION_HASH_REF.

The plot_track method returns an array of the form (SUCCESS, ERROR).
SUCCESS indicates if the method successfully generated a plot.
ERROR contains the reason for any failure.  If the method was
successful ERROR will be undefined.

The TRACK_ARRAY_REF is an array of position arrays.  The position
arrays can be either x,y pairs, or an array of the form
(LATTITUDE, LATTITUDE_DIR, LONGITUDE, LONGITUDE_DIR).  The plot
will be centered around the first position in the TRACK_ARRAY_REF.

The OUTPUT_FILE is the full path of the filename to use as output.

The OPTION_HASH_REF contains configuration options for the plot.
The valid option keys, descriptions, and default values are given below.

	x_pad:		Determines the additional X padding for the plot.
			Defaults to 1.

	y_pad:		Determines the additional Y padding for the plot.
			Defaults to 1.

	x_scale:	Scales the radius value returned by the
			radius_function method for use in determining
			the xrange of the plot.
			Defaults to 1.

	y_scale:	Scales the radius value returned by the
			radius_function method for use in determining
			the yrange of the plot.
			Defaults to 1.

	title:		Sets the plot title.
			Defaults to 'Storm Tracking Map'.

	term:		Sets the gnuplot terminal type.  See gnuplot
			documentation for more details.
			Defaults to 'gif'.

	temp_dir:	Sets the directory to use for writing temporary
			configuration and data files.
			Defaults to '/tmp/'.


=item plot_radius_function(CONTOUR_OUTPUT_FILE, SURFACE_OUTPUT_FILE, OPTION_HASH_REF)

Creates a 2D contour and 3D surface plot of the radius function.  This
enables the user to better visualize the radius function and how it is
being interpolated from the provided node values.  The 2D contour plot overlays
the world map provided by the map_file during construction of the
C<Geo::GNUPlot> object.

The CONTOUR_OUTPUT_FILE is the full path of the filename to use for the contour plot.

The SURFACE_OUTPUT_FILE is the full path of the filename to use for the surface plot.

The OPTION_HASH_REF is identical in format to that used for the plot_track method, except
only the temp_dir and term key value pairs are needed or required.

The plot_radius_function method returns an array of the form (SUCCESS, ERROR).
SUCCESS indicates if the method successfully generated the plots.
ERROR contains the reason for any failure.  If the method was
successful ERROR will be undefined.


=item radius_function(POSITION_ARRAY_REF)

Provides direct access to the radius_function internally
used to compute plot window sizes.  This can be useful for
things such as sorting positions by interest level or
debugging changes to the radius function.

The POSITION_ARRAY_REF has the same two possible
forms as each element of the TRACK_ARRAY_REF argument
of the plot_track method.

=back

=cut

=head1 AUTHOR

James Lee Carpenter, Jimmy.Carpenter@chron.com

=head1 SEE ALSO

	Geo::StormTracker
	gnuplot
	perl(1).

=cut

=head1 ADDITIONAL REFERENCES

=over 4

=item gnuplot

	http://www.cs.dartmouth.edu/gnuplot_info.html 
        http://members.theglobe.com/gnuplot/ 
        http://www.geocities.com/SiliconValley/Foothills/6647/

=item linear interpolation

	Numerical Recipes in Fortran 77
	Second Edition
	(The Art of Scientific Computing)
	Authors:  William H. Press
		  William T. Vettering