CALL BARPLT(X,Y,NPTS,DIA,ISYMB,ILINE) -- This routine produces 
 a bar (step) plot.  Vertical segments are equally spaced between 
 points, end  points are centered in horizontal segment.  FCTR: BA
 
 X,Y - Arrays which define the steps in units of the axes.
 NPTS - Number of points.
 DIA - Diameter of the symbols in scale inches, if DIA .LE. 0. then only
       lines will be drawn.
 ISYMB - Symbol type, see SUBROUTINE SYMBOL.  If ISYMB .LE. 0 then only
         lines will be drawn.
 ILINE - Line type, see SUBROUTINE DSHPLT.  If ILINE .LE. 0 then only
         symbols will be plotted.