Folks,
I'm confused now. Are we proposing that we could have CF-compliant
files that have no valid coordinate data, with the justification that
somebody may figure the coordinates out later?
-Rich
On Thu, Mar 29, 2012 at 1:01 PM, Steve Hankin <steven.c.hankin at noaa.gov> wrote:
> Returning to Nan's valid example, the proposed wording isn't very attuned to
> the valid needs of (in situ) observations.? If the pressure sensor fails,
> while other sensors remain active, then the Z auxiliary coordinate becomes
> unknown but other parameters remain valid.??? The observations have
> potential value (though greatly degraded, of course), because a future
> investigator may figure out how to estimate the Z position from other
> information.? For the investigator writing those applications, the
> statements below are wrong or misleading.
>
> I think the right thing to say is something along the lines of
>
> "Application writers should be aware that under some (rare) circumstances
> data auxiliary coordinate values may be missing, while other parameters at
> the corresponding indices remain valid.?? While special purpose applications
> may be able to glean useful information at these indices, most applications
> will want to regard data as missing where the auxiliary coordinates are
> missing "
>
>
> On 3/29/2012 9:05 AM, Jim Biard wrote:
>
> All,
>
> For the work I am doing right now, I am required to?not?fill in missing
> values in any variable. ?I encourage everyone to go with John Caron's idea.
>
> Grace and peace,
>
> Jim
>
>
> On Thu, Mar 29, 2012 at 12:01 PM, John Caron <caron at unidata.ucar.edu> wrote:
>>
>> To answer this concern, I would agree to modify the statement
>>
>> "Applications are free to assume that data is missing where the auxiliary
>> coordinates are missing"
>>
>> to
>>
>>
>> "Applications should treat the data as missing where the auxiliary
>> coordinates are missing"
>>
>> My concern is that we shouldnt make a file "non CF compliant" just because
>> the data provider would like to store data values where there arent
>> coordinate values. But telling them that standard software _will_ ignore
>> them seems good.
>>
>>
>>
>>
>> On 3/29/2012 9:47 AM, Rich Signell wrote:
>>>
>>> Jonathan,
>>>
>>> +1 on ?your idea of only identifying variables as aux coordinate
>>> variables once they have valid values at valid data locations.
>>>
>>> -Rich
>>>
>>> On Thu, Mar 29, 2012 at 11:32 AM, Jonathan Gregory
>>> <j.m.gregory at reading.ac.uk> ?wrote:
>>>>
>>>> Dear Jim
>>>>
>>>> We are discussing auxiliary coordinate variables. They do not have to be
>>>> 1D or monotonic. Those requirements apply to coordinate variables in the
>>>> Unidata sense. CF distinguishes these two concepts in Sect 1.2.
>>>>
>>>>> The point is, the information in the variable *is* coordinate
>>>>> information,
>>>>
>>>> I would say, if it's missing, it's not information.
>>>>
>>>>> What if we say something along the lines of, "Applications should treat
>>>>> the
>>>>> data as missing where the auxiliary coordinates are missing when
>>>>> plotting
>>>>> data."? ?Would that resolve the problem?
>>>>
>>>> Plotting is not the only thing that an application might wish to use it
>>>> for.
>>>> If we said, more generally, "Applications should treat the data as
>>>> missing for
>>>> all purposes where the aux coord variables are missing", it would be
>>>> almost
>>>> the same as not allowing missing data in aux coord vars, since there
>>>> would be
>>>> no point in providing a data value if it was not permitted to use it.
>>>>
>>>> Although I am arguing one side, I could be convinced either way. But it
>>>> does
>>>> feel unsafe to me at present.
>>>>
>>>> Cheers
>>>>
>>>> Jonathan
>>>> _______________________________________________
>>>> CF-metadata mailing list
>>>> CF-metadata at cgd.ucar.edu
>>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>
>>>
>>>
>>
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>
>
>
>
> --
> Jim Biard
> Research Scholar
> Cooperative Institute for Climate and Satellites
> Remote Sensing and Applications Division
> National Climatic Data Center
> 151 Patton Ave, Asheville, NC 28801-5001
>
> jim.biard at noaa.gov
> 828-271-4900
>
>
>
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>
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--
Dr. Richard P. Signell?? (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598
Received on Thu Mar 29 2012 - 11:11:40 BST
