On 3/25/2013 10:40 AM, Jonathan Gregory wrote:
> Dear Ken
>
>> Thanks for your response too (copied here? is it bad form in a listserv to consolidate responses like this?)
> I think it's convenient, myself!
>
>> That answer seems so easy and obvious that I wonder if I asked the question properly! I'll have to ask Tim to be sure, but I think the standard deviation is the standard deviation over time, of means generated in each time-area-depth cell.
>> But I think the question still remains about being able to use a standard name, which we would like to do of course? I am pretty sure in this example for this standard deviation variable we should NOT use sea_water_temperature for standard_name, and that it would be good if there were more standard name modifiers to choose from. If there were, perhaps we could set standard name to something like "sea_water_temperature standard_deviation".
> You *should* use sea_water_temperature as the standard_name. The standard_name
> alone is not to be regarded as the description of the metadata. It has to be
> taken in combination with cell_methods and modifiers. Maybe it seems more
> surprising that a temporal standard deviation of sea_water_temperature has
> sea_water_temperature for its standard name, but it's really the same kind of
> idea - i.e. a statistic - as a temporal mean or a temporal maximum, isn't it.
> Even if it was variance its standard_name would be sea_water_temperature, and
> in that case the units would be different too.
Hi Jonathan,
What you have just described is the state of CF standard_name today.
But elements of it remain problematic. What do you see as the *purpose*
of CF standard_names? What are the use cases by which standard_names
will lead to better interoperability?
One use case that we are already seeing is that standard_name attributes
are harvested from CF files and used in search engines. If a variable
named as sea_water_temperature in a file is really
time_variance_of_sea_water_temperature, because of its cell_methods,
then we need to be pro-active in making sure that the search engines
harvest the information found in cell_methods, too. This level of
sophistication has not yet emerged into the ISO metadata world. I'm
concerned that if we invoke sophisticated ISO machinery(*) to solve the
problem, we may have a solution in name only -- will this level of
complexity have a hope of becoming widely enough used to bring
interoperability?
- Steve
* Our colleague Dave Neufeld at NOAA/NGDC has pointed out that the ISO
"lineage" model may address the semantics of cell_methods --
https://geo-ide.noaa.gov/wiki/index.php?title=ISO_Lineage.
>
> Cheers
>
> Jonathan
Received on Mon Mar 25 2013 - 12:00:17 GMT
