Chris,

That's a completely valid suggestion. We have to consider implications for backwards compatibility. Among other things, UDUNITS would need to change their convention, since CF follows UDUNITS in this matter, as with all other units. There's nothing that says we can't make changes. I was explaining the "is" as opposed to the "could be" with time units.

Grace and peace,

Jim


On 9/15/16 7:26 AM, Little, Chris wrote:
Jim and Chris B,

I would like to weigh in here, please?

Adhering to UDUnits has merits, but once one adopts ISO8601-like notations, as 
there is no way of specifying otherwise, people assume it *is* ISO8601 and 
therefore a string without a time zone marker indicates local time (whatever 
that is - Solar? Mean Solar? Sidereal? National legal?)

There is work just starting in the OGC/ISO pipeline on how to indicate a 
non-Gregorian calendar using ISO8601 like notation, for the WKT communities.

Personally, I would advocate ISO8601 strict adherence, as most of the 
recommended best practices and profiles, such as RFC3339, are generally strict 
subsets of ISO 8601.

Chris


-----Original Message-----
From: CF-metadata [mailto:[email protected]] On Behalf Of 
[email protected]
Sent: Wednesday, September 14, 2016 10:02 PM
To: [email protected]
Subject: CF-metadata Digest, Vol 161, Issue 3

Send CF-metadata mailing list submissions to
        [email protected]

To subscribe or unsubscribe via the World Wide Web, visit
        http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
or, via email, send a message with subject or body 'help' to
        [email protected]

You can reach the person managing the list at
        [email protected]

When replying, please edit your Subject line so it is more specific than "Re: 
Contents of CF-metadata digest..."


Today's Topics:

    1. nitpick in time axes example (Chris Barker)
    2. Re: nitpick in time axes example (Jim Biard)


----------------------------------------------------------------------

Message: 1
Date: Wed, 14 Sep 2016 12:34:11 -0700
From: Chris Barker <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [CF-metadata] nitpick in time axes example
Message-ID:
        <CALGmxE+S80kd1CnD-55btZZhz=vko-bbbps-bv2w2a-bu0w...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

I see in teh doc:

Example 4.4. Time axis

double time(time) ;
   time:long_name = "time" ;
   time:units = "days since 1990-1-1 0:0:0" ;

IIUC, ISO 8601 requires two digits for the time pieces [1], so that should
be:

"days since 1990-1-1 00:00:00"


The parser I use isn't picky about this, but maybe some are?

BTW, as it's an example, we should probably throw a time offset on there,
too:

"days since 1990-1-1 00:00:00Z"


or

"days since 1990-1-1 00:00:00+00:00"


[1] at least according to wikipedia:
https://en.wikipedia.org/wiki/ISO_8601#Times


-Chris



--
CICS-NC <http://www.cicsnc.org/> Visit us on
Facebook <http://www.facebook.com/cicsnc>         *Jim Biard*
*Research Scholar*
Cooperative Institute for Climate and Satellites NC <http://cicsnc.org/>
North Carolina State University <http://ncsu.edu/>
NOAA National Centers for Environmental Information <http://ncdc.noaa.gov/>
/formerly NOAA’s National Climatic Data Center/
151 Patton Ave, Asheville, NC 28801
e: [email protected] <mailto:[email protected]>
o: +1 828 271 4900

/Connect with us on Facebook for climate <https://www.facebook.com/NOAANCEIclimate> and ocean and geophysics <https://www.facebook.com/NOAANCEIoceangeo> information, and follow us on Twitter at @NOAANCEIclimate <https://twitter.com/NOAANCEIclimate> and @NOAANCEIocngeo <https://twitter.com/NOAANCEIocngeo>. /


_______________________________________________
CF-metadata mailing list
[email protected]
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata

Reply via email to