Improve unit representation in EMMO

[markdoerr]

Please revise unit representation in EMMO:

There is a long (arbitrary) list of derived units, like "ElectricPotentialPerTemperatureUnit", "ElectricPotentialPerTimeUnit", ...
which could be infinitely extended by all combinatoric combinations.

(There are also an arbitrary (?) list of non-SI units).

To keep EMMO compact, wouldn't it make sense to restrict the ontology to base SI units only ? (Everything could be derived from them)

Please also keep in mind simple competency questions, that should be easily answerable with SPARQL queries,
like "Which SI unit has the length measurement ?"

[jesper-friis]

You are right, the list of SI dimensional units is large.

People often works with datasets with units like "mA/cm2" and need to refer to them. Because of this demand, we have included most of the units from QUDT. By default EMMO imports the coherentsiunit module, but not prefixed units. Only the SIDimensionalUnit subclasses that are needed to categorise any of the included units are included in EMMO. The intention of these SIDimensionalUnit subclasses are exactly to answers questions like "Which unit has the length measurement?"

The recommended way to use EMMO in your domain ontology is to just import those modules you need. That way you avoid bloating your domain ontology.

Regardless of that, it is worth to discuss what units modules that should be imported by default.