The -grib_out option writes the grid values to a
specified file in grib2 format. Normally you would use the
-grib option as that requires less time and preserves
the precision of the data. You would only use the
-grib_out option when you have modified
the grid values by using the -undefine or a
similar option. Use the -set_grib_type option
to specify the grib packing.
$ wgrib2 new.grb2 -undefine out-box -10:10 20:40 -grib_out small.grb2
1:0:d=2005082812:HGT:1000 mb:78 hour fcst:
The above routine sets all the grid points outside the 10W-10E 20N-40N to
undefined and then writes the resultant field as a grib file
in small.grb2. This file will be much smaller than the original field.
Hint: by proper use of the -undefine and -grib_out options, one
should be able to send horizontal boundary conditions for
regional models very very quickly. Imagine just sending
4 lines of horizontal boundary conditions.
See also: -text,