CALL SEQUENCE...
       xplot  xin input output [-t1 VAL1 -name VAL2 -lv1 VAL3 \ 
                                -a VAL4 -b VAL5 -c VAL6 \ 
                                -kind VAL7 [VAL8] -label VAL9]
 
 
      DESCRIPTION...
       PLOTS SINGLE LEVEL ZONAL/MERIDIONAL CROSS SECTION CURVE
 
 
      AUTHOR  - N.E.SARGENT
      LAST REVISION: $Header: Autres-corrections-d-usages-de-MAXW-NWDS-modifs-dans-GGSIGN-SIGNAG @ 2018-06-05 17:00:06 -0400 (dugas) $
 
 
      PURPOSE - PLOTS GLOBAL ZONALLY/MERIDIONALLY AVERAGED SINGLE LEVEL FIELD
                VERSUS LATITUDE/LONGITUDE.
 
 
      INPUT FILE...
       XIN = FILE CONTAINING CURVES TO BE PLOTTED. NOTE THAT MULTI-LEVEL
             ZONAL RECORDS WILL NOT BE TREATED BY XPLOT. CONVERSION USING
             THE -SINGLZ KEYWORD SHOULD BE DONE AS A PRELIMINARY STEP.
 
 
      INPUT PARAMETERS (FIRST LINE)
       NSTEP   (t1)   = TIMESTEP NUMBER (BLANK INPUT DEFAULTS TO -1)
       NAME           = NAME OF VARIABLE TO BE PLOTTED
                        THE NAMES 'NEXT' AND 'SKIP' ARE RECOGNIZED BUT FILE XIN
                        IS REWOUND BEFORE EACH SEARCH. THIS ALLOWS FIELDS TO BE
                        IN ANY ORDER ON THE FILE, BUT 'NEXT' ALWAYS SELECTS THE
                        FIRST FIELD AND 'SKIP' IS A NULL OPERATION. THE DEFAULT
                        IS 'ALL', WHICH IMPLIES PLOTTING ALL RECORDS.
       LEVEL   (lv1)  = LEVEL NUMBER (BLANK INPUT DEFAULTS TO -1)
       YLO,YHI (a,b)  = LOWER,UPPER LIMITS OF VERTICAL AXIS.
                        TICK MARKS DIVIDE THE AXIS INTO 10 DIVISIONS BETWEEN
                        YLO AND YHI. A SOLID LINE IS DRAWN AT Y=0 IF YLO.LT.0.
                        AND YHI.GT.0.,  BUT AT YLO OTHERWISE. IF YLO=YHI, THE
                        PROGRAMS USES AUTOMATICALLY DETERMINED VALUES.
       MS             = PRINTER PLOT PARAMETER (NOW IGNORED).
       FMISS   (c)    = LOWER BOUND FOR VALUES TO BE PLOTTED.  IF VALUES ARE
                        MISSING AT SOME LATITUDE,  CODE THEM AS LESS THAN FMISS
                        AND NO POINT WILL BE PLOTTED FOR THAT LATITUDE, (VALUES
                        LESS THAN FMISS ARE NOT PLOTTED).
                        FMISS=0 OR BLANK DEFAULTS TO FMISS=-36.E36 .
       NZMS   (kind1) = 0/1 FOR ZONAL/MERIDIONAL PLOT.
       VKIND  (kind2) = VERTICAL LEVEL TYPE. IT CAN ONLY BE USED WITH CMC/RPN STD
                        FILES AND THEN LV1 AND LV2 ARE ASSUMED TO CONTAIN DECODED
                        VALUES. FURTHERMORE, THIS PARAMETRE CAN ONLY BE SPECIFIED
                        IN COMMAND-LINE MODE. THE CURRENTLY SUPPORTED VALUES ARE:
                        'HAUTEUR'   , heights (m) with respect to sea level
                        'SIGMA'     , classical terrain following (0.0 -> 1.0)
                        'ETA'       , first version of the GEM ETA coordinate
                        'PRESSION'  , pressure (mb)
                        'ARBITRAIRE', arbitrary level (no units apply)
                        'HAUTEURS'  , heights (M) with respect to the surface
                        'HYBRIDE'   , hybrid GEM coordinate
                        'THETA'     , potential temperature coordinate
                        'GALCHEN'   , GalChen generalized coordinate
 
      INPUT PARAMETERS (SECOND LINE)
       LABEL          = 80 CHARACTER LABEL PRINTED ABOVE PLOT.
                        THE DEFAULT IS 'AUTOMATIC', WHICH IS
                        APPROPRIATE WHEN NAME='ALL'.
 
       FURTHERMORE, WHEN NAME='ALL', THE ACTUAL PRINTED LABEL WILL
       BE THE SUPPLIED LABEL PLUS (IF THIS LAST IS SHORT ENOUGH)
       THE RECORD ORDINAL, THE VARIABLE NAME, LEVEL AND TIMESTEP
       (THESE REQUIRE 38 CHARACTERS TO BE PRINTED IN THE LABEL).
 
      READ(5,5010) NSTEP,NAME,LEVEL,YLO,YHI,MS,FMISS,NZMS
      READ(5,5012,END=902) LABEL
 5010 FORMAT(10X,I10,1X,A4,I5,2E10.0,I5,E10.0,I5)
 5012 FORMAT(A80)
 
 
      EXAMPLE OF INPUT CARDS...
 
   XPLOT         182  SUB    1   -5.0E-5    5.0E-5    1   -1.0E-4    0
   JUL ZONALLY AVERAGED E-P (KG M-2 S-1), SHUTZ AND GATES.
 
         0123456789012345678901234567890123456789012345678901234567890
         1         2         3         4         5         6         7
 
 
      EXIT CONDITIONS...
        0 NO PROBLEMS
 
      FATAL CONDITIONS...
        1 UNABLE TO READ DIRECTIVES CARD
        2 UNABLE TO READ LABEL CARD
        3 FOUND MULTI-LEVEL ZONAL RECORD
 
      NON-FATAL CONDITION...
      101 FINISHED READING XIN