[Fwd: Re: [Fwd: [CF-metadata] CF compatibility with NetCDF version 2.4?]]

From: John Caron <caron>
Date: Wed, 04 Dec 2002 09:31:00 -0700

-------- Original Message --------
Subject: Re: [Fwd: [CF-metadata] CF compatibility with NetCDF version 2.4?]
Date: Wed, 04 Dec 2002 08:37:23 -0700
From: Russ Rew <russ at unidata.ucar.edu>
Organization: UCAR Unidata Program
To: John Caron <caron at unidata.ucar.edu>

> do you know any reason why netcdf 2.4 might cause problems with CF-1.0?

No, I think it should work fine, except possibly for the use of the
NC_BYTE data type. In netCDF-2, whether the external NC_BYTE type
represented signed or unsigned values was left up to the user. In
netcdf-3, we treat NC_BYTE as signed for the purposes of conversion to
short, int, long, float, or double. So if the CF conventions call for
representing any data as NC_BYTE type, the netCDF-2 interfaces on some
platforms would treat it as signed and on others as unsigned, but
netCDF-3 utilities would treat it as signed.

Another minor point is characters allowed in names. In netCDF-2,
there was no checking that the characters used in the name of a netCDF
object were compatible with CDL restrictions. The ncdump and ncgen
utilities that use CDL permit only alphanumeric characters, "_", "-",
and "." in names. With netCDF-3, this restriction is also enforced by
the library for *creation* of new dimensions, variables, and
attributes, but previously existing components with less restrictive
names work OK in netCDF-3.

--Russ
Received on Wed Dec 04 2002 - 09:31:00 GMT