NAME:
  plotpcomc
 PURPOSE:   (one line only)
  Plot model fit residual files for Pluto-Charon map fitting
 DESCRIPTION:
  The goal is to plot only the data from the same apparition or same mutual
    event on the same page.  The input file is a little complex.
  This program will plot Pluto-Charon photometric data with the model
    predictions.  The data file for input to this program is generate by
    a run of the spot modeling program SPOTS.  The input file contains
    several parts.  The first line is always an identification line so
    that the program can intelligently disregard old or incorrect format
    files.  There are three keywords that will appear in the rest of the
    file:  VALUES, TEXT, and DATA.  VALUES contain one number per line
    plus a short description of the value.  These are values intended for
    the use of this program and is made to be easy to read by the
    program.  TEXT indicates that 'free form text' follows.  This is the
    information that will appear in the annotation window on the hardcopy
    plots.  This program makes now attempt to understand the information
    contained within, it is intended to be easily read by a human looking
    at the plot.  Within this window there are three fields of
    information.  Column 1 is an attribute, of which there are 3: s -
    skip a line, l - left justify a line, and c - center line.  Column 2
    contains a single digit number.  s# ==> skip # lines.  l# ==> left
    justify with # chars indentation.  # is ignored if line is to be
    centered.  Column 3 thru 42 contain the text.  Anything beyond 42 is
    silently ignored.  The end of text is flagged by DATA appearing in
    the text window.  For this reason all of the keywords begin in column
    three, I didn't want to put in fancy code for parsing the input
    line.  Once DATA begins it is to continue until the end of the file.
  As the file is read the data are classified as out-of-eclipse or
    mutual event data.  Data will be flagged as event data when the following
    conditions are met: 1) longitude is within 10 degrees of either 0 or 180
    degrees and 2) two points that fall within 1 hour of each other.  All
    subsequent data will be taken as part of the event until the time jumps
    by more than 6 hours.  If the data is not recognized as event data, then
    it is taken to be out-of-eclipse photometry and plotted against the
    entire longitude range.  Event data, on the other hand, is plotted
    against time.
 CATEGORY:
  2-D plotting
 CALLING SEQUENCE:
  plotpcomc,file
 INPUTS:
  file - name of residual file
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
 OUTPUTS:
  Screen grabs of each plot (there will be many).
 KEYWORD OUTPUT PARAMETERS:
 CONFIGURATION:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
  Written by Marc W. Buie, Southwest Research Institute, 2023/05/08,
    cloned from an ancient program written in Fortran using the Mongo
    plotting library