Groups can have quite significant performance issues when the datasets are large... something to keep in mind while designing standards or conventions that _require_ the use of netCDF4 groups. It's a last resort, in my opinion... to be used only if there's simply no other way to express what you want.
thanks,
Erik Quaeghebeur writes:
> Dear list,
>
>
> I have not come across any mention of netCDF4 groups (and other netCDF4
> features) in the CF conventions. I was wondering if there are nevertheless
> standard ways to use groups.
>
> For example, I have repackaged some statistics data (csv files) from met
> masts in netCDF4. I've been trying to apply the CF conventions, but bump into
> issues, e.g., of duplication.
>
> Currently, the structure I use is:
>
> root level:
> * time dimension/variable
> * per-instrument-type groups
>
> instrument level:
> * height (of instrument) dimension/variable
> * instrument metadata attributes (not covered by CF conventions)
> * signal groups (some instruments measure more than one signal)
> signal level:
> * signal specific metadata, e.g., units (covered by CF conventions, but for
> variables)
> * signal statistics variables
>
> statistics variables:
> * data
> * some statistic-specific attributes like cell_methods
> * should I duplicate the signal metadata such as unit here?
>
> The group structure is helpful, because its structure improves
> self-descriptiveness, I feel. I guess the structure is also a form of
> metadata. But perhaps it is considered out-of-scope for the CF conventions?
>
>
> Best,
>
> Erik
>
>
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Received on Mon Mar 26 2018 - 08:57:47 BST
