[Esip-documentation] ACDD questions

[Nan Galbraith]

Hi Ted -

If the goal of this sub-group is to make ACDD more useful to a
wide variety of users, we can and should do it in an implementation-
agnostic way, by agreeing on a set of useful discovery terms and
their meanings.  Mapping these to ISO and/or OGC structures and
providing implementation examples in HDF and NetCDF (3 and 4) will
make this standard more useful. Is that what you mean by 'patching
a few symptoms' ?

We have an offer on the table to provide the first draft of definitions,
and that seems like a logical starting point.

Cheers - Nan


On 4/22/13 5:17 PM, Ted Habermann wrote:
> Nan et al.,
>
> Most of these concerns are discussed at 
> http://wiki.esipfed.org/index.php/NetCDF,_HDF,_and_ISO_Metadata along 
> with more general solutions. IMHO, we should go after real cures 
> rather than patching a few symptoms...
>
> Ted
>
>
> On Apr 22, 2013, at 3:37 PM, Nan Galbraith <ngalbraith at whoi.edu 
> <mailto:ngalbraith at whoi.edu>> wrote:
>
>> On 4/19/13 8:15 PM, John Graybeal wrote:
>>> As I had a fair number of comments on the last set of definitions, I 
>>> volunteer to produce a first revision (for discussion of course!) of 
>>> any term definitions you want me to. 
>> That's great. It might be a good idea to cross check against the 
>> definitions
>> that NODC has added -  as part of their NetCDF template project they 
>> wrote
>> some better descriptions. They're at 
>> nodc.noaa.gov/data/formats/netcdf/ 
>> <http://nodc.noaa.gov/data/formats/netcdf/>
>>
>> There are a few categories of terms that need better definitions, IMHO.
>>
>> 1. people:
>> creator_name (recommended)
>> publisher_name (suggested)
>>
>> In a 'normal' research/observing/modeling situation, who are these 
>> people?
>>
>> I think there are 2 necessary points of contact, the person who 'owns'
>> the research and gives you the go-ahead to use/publish the data, and
>> the person who put the data into the file and/or on line. You don't 
>> really
>> need to know how to contact the other contributors, even if they had 
>> equally
>> or more important roles.
>>
>> I believe that NODC recommends naming the principal investigator as 
>> the 'creator' -
>> although in some circumstances there is no single PI, so maybe we 
>> should say this
>> is the person who grants the use of the data.
>>
>> I'm using the publisher as the person who wrote the actual file that 
>> contains
>> the terms, and I'm listing co-PIs and data processors as contributors.
>>
>> 2. file times:
>> date_created (recommended)
>> date_modified (suggested)
>> date_issued (suggested)
>>
>> These could well have different meanings for model data; for my in 
>> situ data, I
>> have 2 (or, for real time data, possibly 3) useful file times; the 
>> time the last edit
>> or processing occurred, which is the version information and could be 
>> useful if
>> the underlying data has been changed,  and the time the file was 
>> written, which
>> could provide information about translation errors being corrected. 
>> (We don't update
>> files, we overwrite them; some people might need to describe the  
>> time the
>> original file was written and time of last update?) For real time 
>> data it could also be
>> interesting to know the last time new data arrived, which could be 
>> asynchronous.
>>
>> NODC doesn't seem to use date_issued, but they have defs for created 
>> and modified.
>>
>> date_created:  "The date or date and time when the file was created.
>> ... This time stamp will never change, even when modifying the file."
>>
>> date_modified: This time stamp will change any time information is 
>> changed in
>> this file.
>>
>> 3.  Keywords - since iso uses keyword type codes instead of cramming 
>> all the
>> possible keywords (theme, place, etc) into one structure, I don't see 
>> why we don't
>> do something similar. We could use our pseudo-groups syntax; 
>> keywords_theme,
>> keywords_dataCenter ...etc.
>>
>> 4. coordinate 'resolution' terms - the word resolution is a poor 
>> choice, and if
>> it's going to be kept, it needs to be defined as meaning 'spacing' or 
>> 'shape' and
>> not an indication of the precision of the coordinate. For 
>> measurements that are
>> irregularly spaced along a mooring line, it's fairly useless - unless 
>> we come up
>> with a vocabulary describing this and other possible values.
>>
>> For my data, the term might be more useful with the other definition; 
>> our depths
>> are approximate 'target depths', and, while we may know the lat/long 
>> of an anchor
>> and of a buoy (the latter being a time series, the former being a 
>> single point)  we
>> don't actually know the lat/long of any given instrument on a mooring 
>> line. The
>> watch circle of the buoy is really the 'resolution' we need to supply 
>> here.
>>
>>
>> Thanks - Nan
>>
>>
>>
>> On 4/19/13 8:15 PM, John Graybeal wrote:
>>> On Apr 19, 2013, at 13:33, Derrick Snowden - NOAA Federal 
>>> <derrick.snowden at noaa.gov <mailto:derrick.snowden at noaa.gov>> wrote:
>>>
>>>> I also think we need another page that serves as the versioned list 
>>>> of attributes (if it's not on the list, it's not part of the 
>>>> convention) and that each attribute contain a well written clear 
>>>> definition.  I think the definitions we have now need to be improved. 
>>>
>>> As I had a fair number of comments on the last set of definitions, I 
>>> volunteer to produce a first revision (for discussion of course!) of 
>>> any term definitions you want me to.
>>>
>>> +1 on multiple keyword vocabularies. The nice thing about being able 
>>> to use a recognizably unique code (e.g., a URI) is that the provider 
>>> can choose what level to provide the keywords, and for what topics, 
>>> and with what vocabularies. I think this will result in more, and 
>>> more accurate, keywords than if we constrain it.
>>>
>>> John
>>>
>>>
>>

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