SAGE Facility MUSTANG metrics Web Service Documentation

ts_percent_availability_total Instataneous percentage of data available

Summary

This metric reports the total portion of data available for the entire requested time period, represented as a percentage. 100% data available means full coverage of data for the requested start and end time. It calculates availability based on information stored in the rapidly-accessible IRIS SEED and PH5 archive database indexes (ts_index), as returned by the service.iris.edu/fdsnws/availability or service.iris.edu/ph5ws/availability web service.

The ts_percent_availability metric is closely related, but reports percentages in 24-hour increments. This metric reports a single total percentage of coverage.

The ts_percent_availability_total metric is currently a prototype that will eventually become a standard MUSTANG metric. Future developments include incorporating metadata information so that percent_availability=0 can be correctly reported when the availability web service returns no information. It is currently not compatible with data in the IRIS PH5 archive.

Uses

ts_percent_availability_total values can be used to give data completeness for a channel over an arbitrary period of time. The metric also indicates the confidence level of data availability for requests from the IRIS DMC.

Data Analyzed

Traces – one N.S.L.C (Network.Station.Location.Channel) per measurement
Window – from start time to the end time of the request
Data SourceIRIS miniSEED archive database time series index (ts_index)

SEED Channel Types – All Time Series Channels

Algorithm

  • Assemble availability web service trace extents for the time duration on each matching N.S.L.C.
  • Sum the data gaps in seconds for this period of time.
  • Calculate the percentage from the ratio of data found (omitting gaps) to data expected for the requested period of time:
    total_duration = end_time - start_time;
    gap_length_total = sum[0..k](start[k+1] - end[k] - (1 / sample_rate[k]));
    percent_available = (total_duration - gap_length_total) / total_duration * 100;
    

Metric Values Returned

value – availability of data expressed as a percentage
target – the trace analyzed, labeled as N.S.L.C.Q (Network.Station.Location.Channel.Quality)
start – beginning of the date requested (UTC)
end – end of the date requested (UTC)
lddateUTC date/time the measurement was made

Notes

If the user specified end date does not include hour:min:sec, then it defaults to 00:00:00

Author(s)

  • Robert Casey

Contact

See Also

Updated