Re: [thredds] Question about FMRC time discrepancy

• To: tom cook <tmcook@xxxxxxxx>
• Subject: Re: [thredds] Question about FMRC time discrepancy
• From: "Signell, Richard" <rsignell@xxxxxxxx>
• Date: Fri, 12 Aug 2016 15:09:52 -0400

Tom,
I think you just have some gaps.  The ending time for the OPeNDAP URL
agrees the number you got from the WMS:

http://nbviewer.jupyter.org/gist/rsignell-usgs/1499308839850aa10bc7281c2437a7b7

On Fri, Aug 12, 2016 at 2:45 PM, tom cook <tmcook@xxxxxxxx> wrote:
> HI
> I have been serving gridded surface currents using FMRC aggregations
> of hourly netcdf files. Yes, I know this is not supposed to work, but
> it has been working fine (as far as I can tell) and much faster than
> ncml aggregations. Anyway, when I go the dataset's TDS page I see:
>
> TimeCoverage:
> Start: 2011-10-01T00:00:00Z
> End: 2016-08-12T18:37:04.088Z
>
> The end time here is obviously the time of the page loading.
>
> The end time in the NetCDF Subset page is shown by
> 2016-08-12T16:00:00Z. The last time in WMS is also
> 2016-08-12T16:00:00.000Z.
>
> Now, when I go to the OPENDAP page, this is what I see
>
>  time: Array of 64 bit Reals [time = 0..42606]
> long_name: Forecast time for ForecastModelRunCollection
> standard_name: time
> units: hours since 2011-10-01T00:00:00Z
> missing_value: NaN
> _CoordinateAxisType: Time
>
> So, from this I can assume that the last time in the data set is
> 2011-10-01 0:00Z + 42606 hrs. However, this is not equal to
> 2016-08-12T16:00:00.000Z, but rather 2016-08-10T07:00:00Z
>
> My first instinct is that there are missing data files, and the
> aggregations are dumb, and assume that each file I add to it is an
> additional hour from my dataset start time. I will run through and
> look for missing data, but is correct thinking? Is there a better
> practice for using FMRC aggregations for large dataset with missing
> times?
>
> Thanks,
> Tom
>
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-- 
Dr. Richard P. Signell   (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598

• References:
  • [thredds] Question about FMRC time discrepancy
    • From: tom cook