[Esip-documentation] ACDD 2-3 question -- date values

[John Graybeal via Esip-documentation]

I see I never summarized the discussion of date_ attributes in ACDD, as I had promised. Sorry and here we go:

As a refresher, the original attributes were date_modified, date_created, and date_issued. They were replaced by date_content_modified, date_values_modified_, and date_product_generated (definitions below).

Two main questions remain unresolved, and a third suggestion.

1) This seems like not enough of a problem, and arguably the solution makes things worse.
2) Should the first item be about ALL content, or just about the NON-VALUES content?
3) The new names date_content_modified and date_values_modified might be clearer as file_values_date and file_date.

Regarding (1): After re-reading all the posts, it seemed a slight majority preferred the change. Many of them were confused by the original names, and some felt they didn't address all use cases. Those who didn't want the change also felt they had a clear understanding of what the previous attributes meant.

Regarding (2): The argument for all content was that many users want a date that indicates when the file was last changed in any way. The argument for non-values content was that it is clearly distinct from the date_values_changed. Not as many letter-writers here, though the authors preferred it as written.

Regarding 3: Alternative names file_date and file_values_date were proposed. The observation was made that the _values_ attribute needed to clearly specify whether it included ancillary variables, which are values in their way. While the original choices were made to avoid the use of 'file' in the name (because not all services are providing files as such), the new names might be clearer anyway. 

I suspect these are resolvable by votes after discussion, if there's a reasonable number of people at the table.

John

New definitions:

date_content_modified 
    The date on which any of the provided content, including data, metadata, and presented format, was last changed (ISO 8601 format)
date_values_modified
    The date on which the provided data values were last changed; excludes metadata and formatting changes (ISO 8601 format)
date_product_generated 
    The date on which this data file or product was produced/distributed (ISO 8601 format). While this date is like a file timestamp, the date_content_modified and date_values_modified should be used to assess the age of the contents of the file or product. 




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John Graybeal
jbgraybeal at mindspring.com
650-450-1853
skype: graybealski