CALL SEQUENCE...
       spslope  IN INPUT OUTPUT [ -kind VAL1 [VAL2] [VAL3] \ 
                                  -a    VAL4 -b  VAL5 -label VAL6 \ 
                                  -name VAL7 -t1 VAL8 -lv1   VAL9]
 
 
      DESCRIPTION...
       spslope - COMPUTES AND PRINTS SPECTRAL M OR N LOGARITHMIC SLOPE
 
 
      AUTHOR   - T.Shepherd, JUL 18/1979.
      LAST REVISION: $Header: Autres-corrections-d-usages-de-MAXW-NWDS-modifs-dans-GGSIGN-SIGNAG @ 2018-06-05 17:00:06 -0400 (dugas) $
 
 
      PURPOSE - CALCULATES AND PRINTS AN ARRAY OF LOGARITHMIC SLOPES OF A
                SPECTRAL FIELDS  (ASSUMED REAL) IN EITHER M OR N-SPACE,
                BETWEEN INITIAL (KI) AND FINAL (KT) WAVENUMBER INDICES.
 
 
      INPUT FILE...
       IN     = GLOBAL SPECTRAL FIELDS.
  
 
      INPUT PARAMETERS...
 
       SPECTYP (kind-1) = 'M' OR 'N' TO DETERMINE DIRECTION
       WEIGHT  (kind-2) = 'W', THEN THE QUANTITIES X(N) ARE WEIGHTED TO MAKE
                          THEM EQUIVALENT TO A TRIANGULAR TRUNCATION.
                          OTHERWISE, WEIGHTING IS SKIPPED.
                          NOTE THAT THIS LAST FEATURE IS ONLY USED FOR A
                          RHOMBOIDAL TRUNCATION, AND AFFECTS ALL N GREATER
                          THAN LM.
       VKIND   (kind-3) = VERTICAL LEVEL TYPE. ONLY USE THIS WITH IN RPN STD FILES
                          AND WHEN LEVX CONTAINS 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
 
       LABEL            = LABEL (80 CHARACTERS MAX).
 
       NI      (1)      = NUMBER OF PAIRS OF WAVENUMBER INTERVALS REQUIRED.
       KI,KT   (a,b)    = PAIRS OF WAVENUMBER LIMITS. (UP TO SEVEN PAIRS, BUT
                          ONLY ONE PAIR WHEN THE COMMAND LINE INPUT IS USED)
       NSTEP   (t1)    \
       NAME    (name)   = RECORD ID FOR FIELDS TO BE SELECTED (DEFAULT ALL)
       LEVEL   (lv1)   /
 
       READ(5,5005) SPECTYP,WEIGHT
       READ(5,5060) LABEL
       READ(5,5010) NI,(KI(I),KT(I),I=1,7)
       READ(5,5015) NSTEP,NAME,LEVEL
 5005  FORMAT(10X,4X,A1,4X,A1)
 5010  FORMAT(15I5)
 5015  FORMAT(10X,I10,1X,A4,I5)
 5060  FORMAT(A80)
 
 
      EXAMPLE OF INPUT CARDS...
 
 *SPSLOPE     N
 * JANUARY 1980 KE ECMWF/WMO
 *  1   10   20
 *                31    K    1
 
         0123456789012345678901234567890123456789012345678901234567890
         1         2         3         4         5         6         7
 
 
      EXIT CONDITIONS...
        0 NO PROBLEMS
        1 UNABLE TO READ SPECTRAL RECORD.
        2 SPECTRAL RECORDS MAY NOT BE GLOBAL
        3 PROBLEM WITH INDEX LIMITS
        4 UNABLE TO READ FIRST  DIRECTIVE CARD
        5 UNABLE TO READ SECOND DIRECTIVE CARD
        6 UNABLE TO READ THIRD  DIRECTIVE CARD