*--------  plotseq_3.hlp = plotseq calling parameters.  --------
*--------  R. Sterner, 23 Sep, 1992

  PLOTSEQ calling parameters.

  plotseq, x, y, [ind]

    INPUT PARAMETERS:

    x = array of x coordinates.  May be 1-d or 2-d.  When x is 1-d all plots
        share same base x array which may be modified by XSCALE.
    y = array of y coordinates.  May be 1-d or 2-d.  If 2-d then second
        index is plot number.

    OUPUT PARAMETERS:

    ind = optional indices of last plotted points. The indices of a subset
          of points may be returned if used with the ZOOM option.


  Keyword parameters will be described in related groups.

  Titles and labels
  -----------------
  TITLE = t_txt  Plot title in a string or string array.
      If t_txt has one element all the plots will have the same title.
      t_txt may have an element for each plot.
  XTITLE = x_txt  X axis title.  Same for all plots (not a string array).
  YTITLE = y_txt  Y axis title.  Same for all plots (not a string array).
  YTICKNAMES = ytn  String array of custom Y axis tick labels.
      Must be used with YTICKVALUES keyword or nothing will happen.
  YTICKVALUES = ytv Numeric array giving Y coordinates of the custom
      Y axis ticks corresponding to the labels given in YTICKNAMES.
      The last two keyword parameters may be used to set up non-standard
      Y axes.  Tick spacing need not be uniform.

  Second Data Set
  ---------------
  XOVER = x2  Second data set x coordinates.  1-d or 2-d.
  YOVER = y2  Second data set y coordinates.  1-d or 2-d.
      Could use to plot a reference curve, maybe a fitted line.

  Axis Control
  ------------
  XRANGE = xrn  A 2 element array giving the X axis range.
  YRANGE = xrn  A 2 element array giving the Y axis range.
  XTYPE = typ   Set X axis to linear (0) or log (1).
  YTYPE = typ   Set Y axis to linear (0) or log (1).
  XSCALE = xsc  A 3 x N array which may be applied to a given 1-d x array
      to vary x axis (1) Offset, (2) Scale, (3) number of points plotted.
      The purpose of XSCALE is to reduce the X array from a N x M 2-d array
      to N element 1-d array and a 3 X M element scaling array.  Ex:
      x = findgen(1000) gives 1000 points in x,
      xscale = off_0  scale_0  n_0
               off_1  scale_1  n_1
                    . . .
               off_m  scale_m  n_m
      where the plotted x for graph j is: off_j + scale_j*x(0:n_j-1)

  Plot control
  ------------
  COLOR = clr  Plot color.
  SYMSIZE = siz  Plot symbol size (def=1) for main data set.

  Grid
  ----
  GH = h   A numeric array giving the Y coordinates of horizontal grid lines.
  GV = v   A numeric array giving the X coordinates of vertical grid lines.
      If either GH or GV or both are given the specified lines are
      available as a grid.  The grid may be turned on or off while running
      the program.
  GCOLOR = gc  Grid color.
  GLINESTYLE = gl  Grid line style (def=solid).