Section 3 contains the product defintion. The structure of the product
definition is described by the product defintion template (PDT). There
are many different PDTs but only some are in common usage. The
-set_pdt option change the current PDT to
another. It often used to change an unsupported PDT to a supported PDT.
For example, a certain graphic program may not support PDT=30 and you
may need to change it to a supported PDT. Changing the PDT will lose
some of the metadata but will allow the graphics program to process
the grib file.
-set_pdt X or
-set_pdt X:Y X=product defintion template number, Y=byte size of PDT if variable-sized PDT
if X has a plus sign, some metadata is copied from the old PDT
$ wgrib2 p.grb -set_pdt 0
1:0:d=2010111618:var discipline=0 center=7 local_table=0 parmcat=255 parm=255:no_level:-1 missing fcst:
$ wgrib2 p.grb -set_set +0
1:0:d=2010111618:PRMSL:no_level:-1 missing fcst: