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Decoders release 2.4.0
- Subject: Decoders release 2.4.0
- Date: Fri, 6 Dec 2002 15:39:58 -0700 (MST)
Hiya,
I'm pleased to announce the beta release of Decoders 2.4.0. This
release includes many changes as well as a new program, 'gribtocdl'.
Most of the changes are to add parameters and levels for new models
and grids, such as the AVN model on a 1-degree grid (avn-1.0x1.0.cdl).
The new 'gribtocdl' program creates a CDL file from GRIB files. Much
of the work was contributed by Arild Burud and Terje Reite from the
Norwegian Service Centre for Climate Modeling at the Norwegian
Meteorological Institute. I wish to thank these developers on behalf
of the Unidata community.
Since this is a beta release, I would appreciate help in testing it
and reporting problems.
A couple of gribtocdl notes:
- Use a representative dataset when creating a CDL file with gribtocdl. If the
dataset is missing a variable, it will also be missing in the CDL.
- Consider the created CDL as a starting point, minor tweaks are usually
needed.
- The external table file feature for variable name override has not
been tested much, but needs to be used with gribtocdl as well as
gribtonc to override variable names.
- Default variable names follow NUWG conventions.
I would have liked to test the code more exhaustively but did not want
to further delay the release. If problems are found, please send email
to address@hidden with information necessary to reproduce
the problem, error messages, and log messages.
Thanks,
Robb...
Included man page from gribtocdl:
User Commands GRIBTOCDL(1)
NAME
gribtocdl - create netCDF CDL-file from GRIB dataset
SYNOPSIS
gribtocdl [-v] [-g tabfile] [-q qspecs] gribfiles
DESCRIPTION
This program decodes GRIB products and generates to stdout
the corresponding CDL code that can be used in gribtonc(1)
to convert the GRIB products to netCDF format. The default
parameter translation is made according to a definition by
UCAR, but the user may supply specific translations in a
separate file by the -g tabfile option. The user-supplied
translations will override the default ones.
OPTIONS
-v Verbose, reports decoding steps to stderr.
-g tabfile
Use GRIB-netcdf translation defined in this file. The
format of this file is described below.
-q qspecs
Specification for how to expand so-called quasi-regular
or thinned grids into rectangular grids. This argument
is a comma-delimited text string that specifies the
method of interpolation used (currently lin for linear
or cub for cubic), and the latitude and longitude in-
crements in degrees for the resulting grid (e.g.
dlat=2.5,dlon=5.0).
FORMAT OF GRIB TO NETCDF TRANSLATION
The format of the translation table is as follows: Each
line contains
GRIB parameter number
netCDF parameter name
netCDF long description
netCDF units
An optional comment
These are all separated by semicolon (";"). To comment a
whole line, put any letter or special character (i.e. not a
digit) in front of it. Trailing spaces are ignored before
each semicolon, but not after. The GRIB number may have
spaces in front. Parameters found in the separate file take
precedence over the default parameter table, those not list-
ed in the separate file are unchanged. All parameters will
be named with a level suffix in addition to the name as-
signed in the separate file.
EXAMPLE
The command
gribtocdl -v -g my.tab sst.grib > sst.cdl
will decode the products in sst.grib and generate the
corresponding CDL code into file sst.cdl. The file my.tab
contains a specific conversion table to be used when naming
a parameter from GRIB. Later the GRIB file may be converted
to netCDF by using gribtonc:
gribtonc -v -g my.tab sst.cdl sst.nc < sst.grib
The file my.tab looks like this:
Grib;netCDF;long name ;units;comments
31 ;CI ;Sea-ice cover ;none ;(0-1)
34 ;SSTK ;Sea surface temperature ;K ;
151 ;MSL ;Mean sea-level pressure ;Pa ;
167 ;T2M ;2 meter temperature ;K ;
SEE ALSO
gribdump(1), gribtonc(1), netcdf(3), udunits(3)
DIAGNOSTICS
Error messages and log messages are written to stderr.
===============================================================================
Robb Kambic Unidata Program Center
Software Engineer III Univ. Corp for Atmospheric Research
address@hidden WWW: http://www.unidata.ucar.edu/
===============================================================================