[CF-metadata] Add new integer types to CF?

Charlie Zender zender at uci.edu
Tue Sep 26 14:39:38 MDT 2017

If there is strong opposition to replacing the valid_* method in
CF <= 1.7 with the _Unsigned method in CF 1.8 then please speak-up.
People seem to prefer _Unsigned (as described in NUG) to the
previous CF standard method (valid_*) as way to allow CDF1, CDF2,
and netCDF4-classic to indicate unsigned integers in CF 1.8.
New datasets could still use the valid_* method but that would
restrict their CF-compliance to <= 1.7. CDF1 and CDF2 and
netCDF4-classic datasets intended for CF 1.8 compliance would have
to use _Unsigned instead of valid_*.

This plan could be enacted with wording like this:

"The netCDF data types char, byte, unsigned byte, short, unsigned
short, int, unsigned int, int64, unsigned int64, float or real,
and double are all acceptable. The char type is not intended for
numeric data. One byte numeric data should be stored using the byte
or unsigned byte data type. Unsigned types should be used for unsigned
data if possible. If the underlying file format does not support
unsigned types, integer or byte variables that are to be interpreted
as unsigned must have the attribute _Unsigned = "true". The convention
explicitly distinguishes between signed and unsigned integer types
only where necessary. Unless otherwise noted, int is interchangeable
with unsigned int, int64, and unsigned int64 in this convention,
including examples and appendices. Similarly short is interchangable
with unsigned short, and byte with unsigned byte."

Comments welcome...
Charlie Zender, Earth System Sci. & Computer Sci.
University of California, Irvine 949-891-2429 )'(

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