C$$$  MAIN PROGRAM DOCUMENTATION BLOCK
C                .      .    .                                       .
C MAIN PROGRAM: MKBND126     CREATE values along boundaries of ngm/eta
C   PRGMMR: ROGERS           ORG: NP22        DATE: 1998-10-19
C
C ABSTRACT: READS IN spectral COEFFICIENT FORM (KMAX LEVELS OF
C   T126 COEFFICIENTS) AND CONVERTS IT TO A IMAX X JMAX "basis" grid
C   for interpolation to the boundary points of the NGM or ETA models
C
C PROGRAM HISTORY LOG:
C   90-05-21  DIMEGO/PAN         CRAY CODE WITH A NEW
C                                SUBROUTINE INTERFACE FOR TRANSFORMS
C   99-02-05  ROGERS             GENERALIZED VERSION WHICH WILL WORK
C                                FOR ANY GLOBAL MODEL RESOLUTION
C                                ADDED PTETABC CODE (INTERPOLATES ETA
C                                BOUNDARY POINTS FROM SIGMA TO ETA)
C                                AS A SUBROUTINE
C USAGE:
C   INPUT FILES:
C     UNIT11    - sigma COEFFICIENTS FROM THE GDAS or aviation
C               - ON KMAX SIGMA LEVELS
C
C   OUTPUT FILES:
C     UNIT6    - DIAGNOSTICS AND PRINT OUTPUT
C     UNIT51   - output FILE OF lateral boundary values
C
C   SUBPROGRAMS CALLED:
C     UNIQUE:    - COF2GRD  COF2xx   DZTOUV   PPZT     PPUV
C                  CMPIND   CMPWND   TRANSI   TRANVI
C                  PLN2H    SUMSHS   SUMVHS   FFTidim
C
C     LIBRARY:
C       SPLIB    - SPTRAN SPTRANV
C
C   EXIT STATES:
C     COND =   0 - SUCCESSFUL RUN
C
C   REMARKS: SEE COMMENT CARDS FOLLOWING DOCBLOCK
C
C ATTRIBUTES:
C   LANGUAGE: STANDARD FORTRAN
C   MACHINE:
C
C$$$
CC
C      VARIABLES IN NAMELIST RGRID READ INTO MAIN PROGRAM
CC
C   POLA    - TYPE OF baSIS GRID  (DEFAULT=FALSE)
C   NORTH   - HEMISPHERE SWITCH FOR baSIS GRID  (DEFAULT=TRUE)
C   ALONVT  - REFERENCE LONGITUDE (+W)      FOR POLA = TRUE
C             STARTING LATITUDE   (+N)      FOR POLA = FALSE
C   POLEI   - I INDEX OF POLE               FOR POLA = TRUE 
C             INCREMENT FOR LATITUDE        FOR POLA = FALSE
C   POLEJ   - J INDEX OF POLE               FOR POLA = TRUE
C             STARTING LONGITUDE  (+W)      FOR POLA = FALSE GRNWCH=360
C   XMESHL  - MESH LENGTH (KM) AT 60N       FOR POLA = TRUE
C             INCREMENT FOR LONGITUDE       FOR POLA = FALSE
C   SI2     - LMAXP1 SIGMA INTERFACE DEFINITIONS