Grib2 geographic subdomain

[Pierre Cassar]

Thank you Wesley for your suggestion:

> Try   wgrib2 -undefine out-box   W:E S:N -grib_out output.grb2
> W,E,S,N are in degrees

This really reduces the big grib2 file size (over 80%) in about 2
minutes.
Cnvgrib on the "reduced" grib2 file now runs in about 10 minutes
(instead of previous 15 minutes) so with this method I save about 3
minutes of precious machine time...
Perhaps it's time to seriously start using GRIB2 format, without
converting to GRIB1... but it's quite hard on my machines (FreeBSD
6.x).

Thank you again.
Pierre Cassar