[CF-metadata] standard names for variables in 'raw engineering' units

From: Karl Taylor <taylor13>
Date: Wed, 11 Mar 2009 13:56:22 -0700

Hi all,

I favor Derrick's view and arguments. It would be nice however to
address John's goals. Can someone think of another way that the
existence of these measurements might be "discovered" and their
potential uses might be made clear?

Karl


Derrick.Snowden at noaa.gov wrote:
> Hi John,
>
> Sounds like a tricky problem, but probably one worth solving. My initial reaction to your question
>
> " Is there a standard technique that would let me convert any existing standard name to a 'raw units' standard name?"
>
> is that this could potentially lead down a difficult road as the mapping is not one to one. A satellite may measure radiance across several wavelength bands which are combined together with independent parameters in an algorithm to estimate SST. Similarly, the same volts measurement from a CTD temperature sensor must be combined with volts measurements from an oxygen sensor (and algorithm parameters) to estimate dissolved oxygen, but independently, the first volts measurement, plus different algorithm/parameters can yield water temperature.
>
> I'm no CF guru, but it seems like the full complexity of mapping raw data (possibly many) + parameters + algorithm = measured value within the CF conventions might be tough. I know SensorML is designed around this idea though, so perhaps there are ideas that can be borrowed from that framework????
>
> I realize this isn't overly helpful but I suppose my point is that during the conversation that might hash out a solution for this within CF, my vote would be for creating standard names for the variable that is actually measured (e.g. volts) rather than semantically try to link engineering unit measurements to physical unit measurements since that relationship is not always straightforward.
>
> I look forward to hearing more from the group.
>
> Best regards,
> Derrick
>
>
> ----- Original Message -----
> From: John Graybeal <graybeal at mbari.org>
> Date: Thursday, March 5, 2009 6:44 pm
> Subject: [CF-metadata] standard names for variables in 'raw engineering' units
>
>> Here's a question about observational variables. Many of our
>> sensors
>> measure variables that are in the standard names list, but the data
>> is
>> not yet converted to science units, for example temperature or
>> oxygen
>> concentration.
>>
>> These measurements are typically represented by a unit like
>> 'volts' (or even 'counts') -- definitely not directly convertible
>> to
>> the canonical units! Is there a standard technique that would let
>> me
>> convert any existing standard name to a 'raw units' standard name?
>>
>> If not, to start the conversation perhaps I can suggest one of the
>> following to indicate such metrics?
>> suffix: _in_engineering_units
>> suffix: _in_raw_units
>> prefix: raw_measure_of_
>>
>> This capabilitiy will be important for finding data that
>> potentially
>> can be converted to the desired values, but has not yet been
>> converted. (Some of our collected parameters are not the primary
>> purpose of the experiment, and they remain in raw units unless
>> someone
>> needs them converted.)
>>
>> John
>>
>> --------------
>> John Graybeal <mailto:graybeal at mbari.org> -- 831-775-1956
>> Monterey Bay Aquarium Research Institute
>> Marine Metadata Interoperability Project: http:// marinemetadata.org
>>
>> _______________________________________________
>> CF-metadata mailing list
>> CF-metadata at cgd.ucar.edu
>> http:// mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http:// mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>
>
Received on Wed Mar 11 2009 - 14:56:22 GMT