[thredds] Question about FMRC time discrepancy

• To: thredds community <thredds@xxxxxxxxxxxxxxxx>
• Subject: [thredds] Question about FMRC time discrepancy
• From: tom cook <tmcook@xxxxxxxx>
• Date: Fri, 12 Aug 2016 11:45:31 -0700

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

• Follow-Ups:
  • Re: [thredds] Question about FMRC time discrepancy
    • From: David Robertson
  • Re: [thredds] Question about FMRC time discrepancy
    • From: Signell, Richard