NAGRIB2 converts gridded data in GRIB2 files to GEMPAK gridded data.

INPUT PARAMETERS
 
    GBFILE    GRIB data file name
    GDOUTF    Output grid file
    PROJ      Map projection/angles/margins|drop flag
    GRDAREA   Area covered by grid
    KXKY      Number of grid points in x;y
    MAXGRD    Maximum number of grids
    CPYFIL    Grid file whose navigation is to be used in new grid file | subare
    GAREA     Graphics area
    OUTPUT    Output device/filename
    G2TBLS    Input GRIB2 decoding tables
    G2DIAG    GRIB2 diagnostic elements
    OVERWR    Overwr flag
 
 

PROGRAM DESCRIPTION
 
    NAGRIB2 will convert gridded data which is in GRIB2 files to
    gridded data in a GEMPAK file.

    The GRIB2 input file is specified in GBFILE.

    The GEMPAK output file is given in GDOUTF. This file will
    be opened if it exists and the projection information
    matches the GRIB message projection. If the file does not
    exist, it will be created using information given by the
    user.  If the output filename is "LIST", the GRIB2 file will
    be scanned and the decoded GEMPAK header information will be
    printed out.

    The navigation information given by the user may take several
    forms. The first possibility is for the user to enter
    CPYFIL=#NNN, where NNN is a grid projection number listed in
    GRDNAV.TBL. Second, the user may enter CPYFIL=GDS. This will
    read the navigation from the Grid Definition Section of the
    first GRIB message. Third, the user could enter CPYFIL=OLDFILE,
    where OLDFILE is the name of an existing GEMPAK file from
    which to copy the navigation information. Last, the user
    may choose to use the PROJ, GRDAREA, and KXKY parameters to
    specify the navigation.

    GAREA is used to subset the grid.  It may be specified as
    any valid input for GAREA which are equivalent to lat/lon bounds
    or as a single @ followed by the lower-left and upper-right grid
    point coordinates separated by semicolons.  In the former case,
    the locations are rounded to the nearest grid points.  The
    projection type and angles entered as described above along with
    the lat/lon coordinates of the corners of the subset define a
    new grid navigation different from that of the full grid.  The
    navigation entered as described in the preceding paragraph is
    always that of the full grid.  To get the full grid, set GAREA to
    blank, GRID or DSET.

    OUTPUT defines the direction and destination of printed output.

    G2TBLS allows the user to override the default GRIB2 decoding tables
    by listing the filenames of the WMO and Local (e.g. NCEP) parameter tables
    and vertical coordinate tables, and the WMO originating center table.

    G2DIAG allows for detailed GRIB2 message section information,
    entry-by-entry, to be printed out for selected GRIB2 messages.
    Simply list those GRIB2 sections to be examined (IS, IDS, GDS, PDS,
    DRS, BMS, or ALL for all sections), e.g., pds;gds.
    Selected GRIB2 messages for examination may also be identified by
    number in list and/or range format, e.g., 2;4;5-9.

    OVERWR is a logical flag that allows the user to overwrite the existing
    GEMPAK grid file.  If OVERWR is YES, then the grid file is being
    overwritten.  Otherwise, it remains the same.


EXAMPLES
 
    1.  Convert the data in the specified NAM GRIB file3.
        Create the GEMPAK file using projection #104 from the
	grid navigation table.  Define a subset using the entry in geog.tbl.


	GBFILE   =  nam.t00z.grbgrd30.tm00
	GDOUTF   =  nam_30.grd
	PROJ     =
	GRDAREA  =
	KXKY     =
	MAXGRD   =  3000
	CPYFIL   =  #104
	GAREA    =  ks-
	OUTPUT   =  t
        G2TBLS   =
        G2DIAG   =


    2.  Convert the 60 hour data in the given GFS GRIB2 file.
	Create the GEMPAK file using the navigation
	information given the Grid Definition Section of the
	GRIB message.  Define a subset using grid coordinates.


	GBFILE   =  gfs.t06z.pgrb2f60
	GDOUTF   =  gfs_60.grd
	PROJ     =
	GRDAREA  =
	KXKY     =
	MAXGRD   =  3000
	CPYFIL   =  gds
	GAREA    =  @230;110;290;140
	OUTPUT   =  t
        G2TBLS   =
        G2DIAG   =


    3.  Convert the data in the GRIB file for global GFS. Create
	the GEMPAK file using the user input for PROJ, GRDAREA and
	KXKY.  Do not do a subset, use the full grid.


	GBFILE   =  gfs.t06z.pgrb2f60
	GDOUTF   =  gfs_60.grd
	PROJ     =  ced/0;0;0
	GRDAREA  =  -90.;0.;90.;-0.5
	KXKY     =  720;361
	MAXGRD   =  3000
	CPYFIL   =
	GAREA    =  grid
	OUTPUT   =  t
        G2TBLS   =
        G2DIAG   =


    4.  Convert the data in the GRIB file for the NDFD Max Temperature grid.
	Override the default decoding parameter tables.


	GBFILE   =  /tmp/ds.maxt.bin
	GDOUTF   =  /tmp/ds.maxt.grd
	PROJ     =
	GRDAREA  =
	KXKY     =
	MAXGRD   =  3000
	CPYFIL   =  gds
	GAREA    =  grid
	OUTPUT   =  t
	G2TBLS   =  /tmp/g2varswmo1.tbl;/tmp/g2varsncep0.tbl
        G2DIAG   =


    5.  Scan a GRIB file and print out the PDS and GDS sections
	for GRIB messages 1, 2, 6 through 12, and 88.


	GBFILE   =  gfs.t06z.pgrb2f60
	GDOUTF   =  LIST
	PROJ     =
	GRDAREA  =
	KXKY     =
	MAXGRD   =  3999
	CPYFIL   =  gds
	GAREA    =  grid
	OUTPUT   =  t
        G2TBLS   =
	G2DIAG   =  pds;gds|1;2;6-12;88


    6.  Convert the data in the GRIB file for the NDFD Max Temperature grid.
        Overwrite the existing GEMPAK grid file.


        GBFILE   =  /tmp/ds.maxt.bin
        GDOUTF   =  /tmp/ds.maxt.grd
        PROJ     =
        GRDAREA  =
        KXKY     =
        MAXGRD   =  3000
        CPYFIL   =  gds
        GAREA    =  grid
        OUTPUT   =  t
        G2TBLS   =
        G2DIAG   =
        OVERWR   = yes


ERROR MESSAGES
 
    [NAGRIB2  +6]   WARNING: Resetting MAXGRD value to max limit ....
    [NAGRIB2 ] ! GRIB version 0 cannot be decoded.
    [NAGRIB2 ] ! Invalid parameter code table version.
    [NAGRIB2 ] ! No valid parameter found for ....
    [NAGRIB2 ] ! No valid vertical coordinate found for ....
    [NAGRIB2  +1]   WARNING: This grid is too large for GEMPAK programs.
    [NAGRIB2  -1]   Fatal error initializing TAE.
    [NAGRIB2  -2]   Fatal error reading TAE parameters.
    [NAGRIB2  -3]   Fatal error initializing GEMPLT.
    [NAGRIB2 ] ! Navigation information is invalid.
    [NAGRIB2 ] ! Grid area ... is invalid.
    [NAGRIB2 ] ! Grid size is invalid.
    [NAGRIB2  -7]   The grid file name may not be blank.
    [NAGRIB2 ] ! Navigation table cannot be read.
    [NAGRIB2 ] ! Grid name ... cannot be found in grid table.
    [NAGRIB2 -10]   Input for GEMPAK output file is blank.
    [NAGRIB2 -11]   Error opening GEMPAK grid file.
    [NAGRIB2 -12]   Error creating GEMPAK grid file.
    [NAGRIB2 ] ! Cannot open GRIB vertical coordinate table.
    [NAGRIB2 ] ! Cannot open GRIB parameter table.
    [NAGRIB2 -15]   Error opening GRIB file.
    [NAGRIB2 -16]   EOF on input GRIB file
    [NAGRIB2 ] ! Error setting date/time.
    [NAGRIB2 ] ! Invalid bitmap specification.
    [NAGRIB2 -19]   Error reading GRIB file.
    [NAGRIB2 -20]   Invalid input for GAREA.
    [NAGRIB2 -21]   Grid is too large.
    [NAGRIB2 ] ! Length of BDS section less than or equal to 0
    [NAGRIB2 -25]   Error unpacking GRIB2 metadata
    [NAGRIB2 -26]   Memory allocation error for next message
    [NAGRIB2 -27]   GRIB Message is not version 2
    [NAGRIB2 -30]   Could not allocate space for grid.
