Hi Doug,
On 7/15/2010 5:32 PM, Doug Lindholm wrote:
> I notice that the THREDDS catalog schema (1.0.2) has maxOccurs="3" for
> these elements of timeCoverageType. What does it mean when start, end,
> and duration are all set?
>
> I'm wondering if it could support the following use case:
> I have a dataset that is updated regularly but published one week after
> the measurement was made. Thus the end of my time coverage is "7 days ago".
>
> I gather that I could define a start time of "7 days ago" by specifying
> end="present" and duration="7days". But if I also specify a fixed date
> for the start time, is it in any way acceptable to interpret the
> duration as an offset from "present"? Any better ideas?
The THREDDS timeCoverageType does not currently support what you need
for the situation you describe. The "timeCoverage Type" section of the
THREDDS catalog specification (along with the "date Type" and "duration
Type" sections) has a pretty good description of what is allowed in a
timeCoverageType element:
http://www.unidata.ucar.edu/projects/THREDDS/tech/catalog/v1.0.2/InvCatalogSpec.html#timeCoverageType
Basically, start and end can contain a date/time string (either
W3C/ISO8601 or udunits) or the text "present"; duration can contain a
duration/period string (again either W3C/ISO8601 or udunits) [see the
spec for more details and references]. If all three elements are present
they must be self consistent.
What it sounds like you need is the ability to do some math relative to
the present. Unfortunately, we don't support this functionality.
Ethan
