Re: [h5md-user] Unit attribute versus non-dimensionless quantities

[Peter Colberg]

Hi Konrad,

On Mon, Sep 09, 2013 at 12:37:48PM +0200, Konrad Hinsen wrote:
> BTW, I wonder if storing data in attributes is really worth the
> trouble it generates, considering units or in fact any other kind of
> annotation.  If size is the motivation, then compact datasets can
> provide nearly the same advantages without the inconvenience.

Thank you, that is a very helpful hint!

Compact datasets [1] are applicable to data of 30 kB or less, which is
stored in the header block of the object. Compact datasets are created
by setting the appropriate layout on the dataset creation property
list using H5Pset_layout [2].

[1] http://www.hdfgroup.org/HDF5/doc/UG/UG_frame10Datasets.html
[2] http://www.hdfgroup.org/HDF5/doc/RM/RM_H5P.html#Property-SetLayout

This allows us to mandate the storage of time-independent data using
datasets, e.g., for fixed-size box information. In consequence, a
“unit” attribute would be attachable to all data in the specification.

Peter