Re: Problems decoding GRIB2 GFS Ensemble grids


The most recent version of dcgrib2 (5.9.3) will store the GRIB2 data in the 
grid file without unpacking the data block, making the GEMPAK file much 
smaller, and the decoding process much faster. The older GEMPAK distributions 
will not be able to read those decoded files however, since they do not know 
how to unpack the GRIB2 data block, so if you use the 5.9.3 decoder, you would 
want to upgrade the other programs as well, or recompile the dcgrib2 program 
from 5.9.3 to use the previous packing method for the data- but you may find 
that unpacking and repacking the data in realtime is quite a load on the LDM 
pqact processing (otherwise, you can use nagrib2 outside of the LDM which will 
be compatible with the previous versions).

I'll add a command line flag to the 5.9.4 dcgrib2 to allow you to select the 
storage method for backward compatibility.

Steve Chiswell
Unidata User Support

On Tue, 2006-10-10 at 01:24 -0600, Kevin R. Tyle wrote:
Hi Steve,

Thanks for the updated files.  I can now get it to work using the
GEMPAK5.9.3 version of dcgrib2 using the corrected tables.  However, even
with the updated tables, versions 5.9.1 and 5.7.4 of dcgrib2 still do not
decode.  Perhaps I shall just recompile dcgrib2 for use in these two
distributions (which are still in operational use here) unless you have
another idea.