[CF-metadata] Best representation of wire-crawling profiler

Steve Hankin steven.c.hankin at noaa.gov
Sun Mar 5 13:04:23 MST 2017


Hi Rich,

This sounds like just the right solution.  It's onsistent with the use 
of precise_lon and precise_lat in Example H.5. (A single timeseries with 
time-varying deviations from a nominal point spatial location)

It's a pretty complicated encoding, though.  To make sure that you get 
interoperability out of using it, it's important that other folks 
generating/analyzing similar data do things the same way.  (NOAA/PMEL 
scientists are generating quite a lot of wire-crawler data, for 
example.)  So it seems like a good idea to write this up as a special 
encoding example that, like H.5., gets explicitly documented in the next 
CF version.

     - Steve

==================================================

On 2/28/2017 11:18 AM, Signell, Richard wrote:
> CF Folks,
>
> Okay, with help from the ERDDAP community
> https://groups.google.com/forum/#!topic/erddap/xfAufA8Qyhg 
> <https://groups.google.com/forum/#%21topic/erddap/xfAufA8Qyhg>
> I think I figured this out:
>
> The solution would be to use nominal "time(profiles)" and 
> "precise_time(obs)".   So we would write something like
>
> https://data.ioos.us/gliders//thredds/dodsC/deployments/rutgers/unit_191-20150105T1443/unit_191-20150105T1443.nc3.nc.html 
> <https://data.ioos.us/gliders//thredds/dodsC/deployments/rutgers/unit_191-20150105T1443/unit_191-20150105T1443.nc3.nc.html>
>
> with both "time" and "precise_time", but instead of using the 
> multidimensional representation, use the ragged representation, like this
>
> http://cfconventions.org/cf-conventions/cf-conventions.html#_ragged_array_representation_of_time_series_profiles 
> <http://cfconventions.org/cf-conventions/cf-conventions.html#_ragged_array_representation_of_time_series_profiles>
>
> So in addition to "precise_time(obs)" we would also have data 
> variables like "temperature(obs)".
>
> Thanks,
> Rich
>
> On Tue, Feb 28, 2017 at 7:27 AM, Signell, Richard <rsignell at usgs.gov 
> <mailto:rsignell at usgs.gov>> wrote:
>
>     CF Folks,
>
>     What would be the best DSG featureType to represent a wire-crawling
>     sensor that has a fixed lon,lat location, but non-uniform depth
>     interval as it goes up and down, and takes enough time that the
>     profile might not be accurately represented with a single time value?
>
>     On this ERDDAP site the featureType is "trajectory":
>     http://ooi-data.marine.rutgers.edu/erddap/info/CP04OSPM-WFP01-04-FLORTK000-flort_kn_stc_imodem_instrument-telemetered-d0005/index.html
>     <http://ooi-data.marine.rutgers.edu/erddap/info/CP04OSPM-WFP01-04-FLORTK000-flort_kn_stc_imodem_instrument-telemetered-d0005/index.html>
>
>     and I'm wondering if that's the best, or whether "timeSeriesProfile"
>     would be better, written as as ragged array with profile_index?
>
>     Certainly if we assigned a "nominal time" for each cast, then it would
>     clearly be representable as timeSeriesProfile, but it's not clear to
>     me that it meets the CF conventions if time varies within the cast.
>
>     There would be value in allowing the time-varying values within the
>     profile, but also labeling/indexing the profiles,  so that people
>     could easily extract, say, all the "down" profiles, excluding the "up"
>     (or vice versa).
>
>     Thanks,
>     Rich
>
>     --
>     Dr. Richard P. Signell   (508) 457-2229
>     USGS, 384 Woods Hole Rd.
>     Woods Hole, MA 02543-1598
>
>
>
>
> -- 
> Dr. Richard P. Signell (508) 457-2229
> USGS, 384 Woods Hole Rd.
> Woods Hole, MA 02543-1598
>
>
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> CF-metadata at cgd.ucar.edu
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