Help for STATPLT

PURPOSE: 

STATPLT generates a plot of the contents of a classification statistics
dataset. The plot consists of the centroids and Bayesian confidence regions
for each class, for any two input bands. If the display of the plot is not 
suppressed The plot is automatically displayed, and if requested, is saved
in an output PostScript file.

EXECUTION:
STATPLT SDS BANDS=(1,5) SIGMA=2.5   
                                    The resultant plot will have DN of
                                    Band 1 as the x-axis and the DN of
                                    Band 5 as the y-axis. Ellipses
                                    representing the 2.5 standard
                                    deviation confidence boundaries will
                                    be drawn around each centroid. The plot
                                    will be automatically displayed and
                                    optionally saved in the output PostScript
                                    file, 'statplt.psf'.

STATPLT SDS XSCALE=(0,100) PLOTNAME=(statplt1.psf)

                                    This plot will have the x-axis 
                                    rescaled such that the range 0 to 100 DN
                                    spans the entire length of the x-axis.
                                    Any class whose Band 1 mean (the band
                                    being plotted on the x-axis) is outside
                                    the 0 to 100 DN range, will not be
                                    plotted.  The plot will be automatically
                                    displayed and optionally saved in the 
                                    output PostScript file, 'statplt.psf'.

STATPLT SDS XSCALE=(0,100) YSCALE=(0,100) PLOTNAME=(statplt.psf)

                                    In addition to scaling both axes for
                                    the range 0 to 100, the plot is not
                                    displayed, but is automatically saved in
                                    the output PostScript file.

OPERATION:
     For each class in a classification statistics dataset (or for those
specified by the size field) STATPLT:

           1.  Marks the position of the centroid of the class.
           2.  Labels the centroid with its corresponding class number.
           3.  Draws the ellipse that bounds the range of the class.
               The number of standard deviations within this boundary
               is specified by the SIGMA parameter.

If the centroid of a class lies outside the range of either the x or y axis,
that class will be ignored.

If the plot display is not suppressed by the use of the keyword 'NODISP, the 
plot is displayed at the user terminal via calls to XRTPS. XRTPS also
displays three menu selections and then waits for the user to select one of
three options before continuing. The three options are; 1) exit, 2)
page, and 3) save. Selecting 'exit' results in immediate termination of
STATPLT.  Selecting 'page' results in immediate termination of STATPLT, as
STATPLT creates only one plot each time that it is run. Selecting 'save' 
results in the displayed image being saved in the output PostScript file, 
followed by the termination of STATPLT.

WRITTEN BY:  Ron Alley, 24 October 1978
COGNIZANT PROGRAMMER:  S. Pohorsky
REVISION: 5 April 1984 (Conversion to VAX)
          Made portable for UNIX and for XRT/graph. J. Turner (CRI) May 1995

        26 Jun 2011 - Ray Bambery - Clean up code to prevent warning messages
                            with gfortran 4.4.4 compiler under Linux. Changed
                            plot routine calls from XRT commercial graphics
                            package to gnuplot. Added class names and centroid
                            positions to graphics.
        03 Jul 2012 - Ray Bambery -  Renamed STATPLT2 for delivery to MIPL
                        power still uses XRT/Graph package, removed debug
                        statements, Removed <tab> in front of continuation
                        lines to make backward compatible with
                        32-bit Linux gfortran 4.2.1, otherwise
                         compatible 64-bit Linux gfortran 4.6.3</tab>
        24 Aug 2012 -lwk- renamed back to STATPLT since it has exactly the
                        same functionality and interface as the old one.

PARAMETERS: