WGRIB is a program to manipulate, inventory and decode GRIB files. The program is known to work on machines ranging from 486s to Cray supercomputers. (One fellow even ported it to a 286!) The program is Y2K friendly (NCO Y2K testing procedure).

wgrib (gributil) is an operational NCEP program. On the IBM/SP, it can be found at /nwprod/util/exec/wgrib,

Highlights for v1.8.x:

• Support for simple-packed spectral data (Luis Kornblueh). Note: you still need spectral -> grid routines.
• Cleanup of triangular grid support (Luis Kornblueh)
  
• New and improved tables
  
• More grid information, including scanning mode
  
• fixed bug in grid vs earth relative north (-v option only)

Highlights for v1.7.x:

• scans entire file for grib messages (D. Haalman)
• Added German Weather Service (DWD) tables 201, 202, 203 and 2
  Support for triangular grid (Helmut P. Frank)
  
• fractional mb (NCEP local extension)
• added new levels
• updated NCEP operational GRIB table
• fixed thinned grids with bitmap
• NCEP ensemble support
• fixed -H option
• Support for the 3/6/12 hour forecast time units
• Fixed a bug with bitmap when the precision is greater than 24 bits. This is more of a theoretical problem as most people (NCEP and ECMWF) limit the precision to 16 bits and I can't imagine anyone using more than 24 bit of precision for any meteorological data. Thanks LB for finding the bug.
• Source code in a tar file. For people who want to read the source code before it is combined into wgrib.c.
• more time codes like SECONDS
• New or updated ECMWF grib tables: 128 129 130 131 140 150 160 170 180

Highlights for v1.6.x:

• fixed a problem with identifying 1997 Reanalysis files.
• fixed a problem with the GDS header in the -H option
• optional binary output of PDS and GDS (-H option)
• -d all (decode entire file)
• thinned grid support
• fix of my mis-interpretation on how year 2000 is stored in GRIB
• NCEP operational table
• updated documentation

Under testing:

• beta version

Note: there were two definitions for SNOC and CWAT in the operational and Reanalysis grib tables. For the time being, I'm calling snow cover "SNOWC" and canopy water "CNWAT."

To do:

• ECMWF ensemble information

Documentation:

• Changes
  
• Introduction
  
• For DOS users
  
• User-defined parameter tables
• NCEP/NCAR Reanalysis user-defined parameter table
• NCEP Operational user-defined parameter table
• ECMWF user-defined parameter table (#128)
• ECMWF user-defined parameter table (#160)
• howto: grib -> ieee
  
• some tricks
  
• Output formats and -H update
  
• operational vs reanalysis parameter table
  
• Previous Notices (mailing list) Mainly bug notices
  
• How to Compile and (misc files)
  

Source code:

• C source code Netscape: shift+left_mouse_button, (If your browser alters the code, use anonymous ftp to download /pub/wgrib/wgrib.c)
• ftp://ftp.cpc.ncep.noaa.gov/wd51we/wgrib (FTP access: documentation, test files, etc.)
• wgrib.tar See above for source code. (For people who want to read or re-use the source code.)

Compiled versions:

• not all links are valid and compiled versions tend to be older versions
• MS-DOS (compiled with gcc)
  
• Windows (compiled with gcc)
  
• SunOS (compiled with acc)
  

Windows: find vs. grep and egrep

You should use grep or egrep instead of the MS-DOS "find" command.
The (e)grep command is more flexible and it is consistent with the
documentation. Public domain versions exist for ms-dos, windows and
Win32 machines. Personally I would look for a grep based on GNU source
code. In your favorite internet search engine look for "+grep +gnu +windows".

2 GB limit, 32 vs 64 bit computers:

Wgrib is limited to 2 GB files when used on 32-bit machines such as a pentium-4. (2 GB is the maximum value of a 32-bit integer.) On 64-bit machines, the 2 gig limit is replaced by a really big number.

Future attractions:

• gribw grib decode/encode library (beta testing)
• ECMWF ensemble meta data

Links:

• wgrib2: wgrib for GRIB-2 files
• Java decoder: jgrib
• Perl utilities: PDL::IO::GRIB

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comments: Wesley.Ebisuzaki@noaa.gov