[Cube/vo-dml] ivoa datatypes

[Rob Seaman]

On Apr 28, 2014, at 12:19 PM, CresitelloDittmar, Mark <mdittmar at cfa.harvard.edu> wrote:

> 
> On Fri, Apr 25, 2014 at 4:55 AM, Gerard Lemson <lemson at mpa-garching.mpg.de> wrote:
> 
> > Request:
> >
> >   During this effort, there are a couple types that I would like to add to this suite.
> >
> >   1) TimeValue: extends AtomicValue
> >
> >         + value: datetime     # ivoa:datetime primitive type
> >         + unit: Unit              # ivoa:unit primitive type.
> >
> 
> 
> 
> Arnold has made some comments about different types of Time value object depending on whether this is absolute or a delta (time since T0).
> Part if my trouble with debating this is not knowing the scope of 'datetime'.  Is there an actual specification of what this covers?  
> If this is just a time instance type (suitable for DATE keyword), then it may not be what is desired under Quantity.

Perhaps start with use cases.  “Time” is arguably the broadest topic in existence.  Before a specification, one needs engineering requirements.  Before requirements, a concept of operations.  What is it you (the collective “you”) are trying to represent and for what purpose?

Rob

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