I think the _Unsigned attribute would have been a grand idea before.
But if we?re now allowing explicit unsigned types, what purpose does it serve?
Do I use the _Unsigned = ?true? attribute on every ubyte, ushort, and uint variable? They?re already clearly unsigned according to the type definition.
it would only be useful if I wanted to keep declaring the variables as byte but wanted folks to treat them as ubyte. This seems perverse.
And would we start putting _Unsigned = ?false? on all of our integer variables? All numeric variables?
Also note that fully supporting the new types means we can have unsigned integer global attributes. Since attributes can?t have attributes, _Unsigned and valid_ don?t help here.
-- Evan
On 9/22/17, 9:55 AM, "Signell, Richard" <rsignell at usgs.gov> wrote:
Folks,
I suggested
_Unsigned = "true"
because that is already supported by Unidata:
http://www.unidata.ucar.edu/software/netcdf/docs/BestPractices.html#bp_Unsigned-Data
http://www.unidata.ucar.edu/mailing_lists/archives/netcdf-java/2013/msg00087.html
_at_Unidata: are you guys are you going to chime in on this?
On Fri, Sep 22, 2017 at 12:40 PM, Charlie Zender <zender at uci.edu> wrote:
> _Unsigned = "true" is cleaner and clearer to me
> than the valid_* attributes.
> To me, Rich's suggestion requires a consensus
> to _drop_ valid_* in CF 1.8, and instead make
> _Unsigned the preferred workaround for file formats
> that do not support unsigned types.
> Unless people want to require _both_
> _Unsigned and valid_* (seems burdensome to me),
> or allow either _Unsigned or valid_* (seems
> crufty to me). What do others think?
>
> On 9/22/17 04:49, Signell, Richard wrote:
>>
>> lookin at the NUG, how about saying:
>>
>> In file types that don't offer native support for unsigned types,
>> integer or byte variables that are to be interpreted as unsigned must
>> have the attribute _Unsigned = "true".
>
> --
> Charlie Zender, Earth System Sci. & Computer Sci.
> University of California, Irvine 949-891-2429 )'(
>
--
Dr. Richard P. Signell (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598
Received on Fri Sep 22 2017 - 11:36:20 BST
