BaseUnit has too many specific units

[ahashibon]

I agree we need to standardise on SI units, however, we not make it more explicit and open and consistent as follows:

1. The BaseUnit class, has subclasses: ElectricUnit, LengthUnit, etc.
2. e.g., LengthUnit will have a subclass BaseLengthUnit which has Metre and other units
3. alternatively, LengthUnit has a subclass all possible units needed, and the Meter will also inherit from BaseSiUnit, which is another class we need to have.

In this way we eliminate the clutter in the actual quantities having to add possible units in the class definition. For example:

for Area, we simply put

hasUnit Some AreaUnit,

isn't this much more elegant?

@emanueleghedini @jesper-friis your comments please?

thanks.

[ahashibon]

same thing for

why have seconds and days etc... this should be changeable for each User Case, and hence propose here and in all quantities to just on the top EMMO levels mention the type of unit:

Time hasUnit TImeUnit

and TimeUnit is the superclass of all relevant time units, like seconds, days, minutes, hours, MarchianHouers, etc...

[jesper-friis]

I agree that this is not very clean. I think we simply should remove all the hasUnit relations from the physical quantities and only associate units their corresponding physical quantity.

[jesper-friis]

This also solves the conceptual mistake that Emanuele pointed out.

Agree?

[jesper-friis]

The physical dimensions introduced in 1.0.0-alpha solves this in a clean way.