Complex Unit Support (Volume related to temperature)

[expertalex]

Thanks a lot for your workI The API Design is amazing and I was interested on it and sow that Volumes and Weights are not linked to Temperature.

For example We Sometimes want to Convert Between Liters at 15 Degrees to Galons at 50 Degrees for a particular substance.

Is your Framework designed to add relationship between Base Units? Or can we creare more advanced units based on the API?

CompexVolume = { Volume and Temperature }

See: When is a Litre not a Litre?
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/283253/laymans-guide-on-sta-measurement-v2-march_2011.pdf

[raynigon]

Another "Complex" Unit would be Newton-metre (torque). Currently i need to extend the indriya implementation because the unit api does not specify torque as its own quantity. Would be really nice to see it here.

[keilw]

Not sure, if you need a separate quantity for the volume at a particular temperature case? It could be more of a formula, but if a quantity was needed, it would at most be for https://github.com/unitsofmeasurement/uom-systems/tree/master/quantity or even in a custom module including uom-domain. @andi-huber, @dautelle or @desruisseaux any thoughts on that?

Torque has been around for a while now: https://github.com/unitsofmeasurement/si-units/blob/master/quantity/src/main/java/si/uom/quantity/Torque.java

[keilw]

I will move this to https://github.com/unitsofmeasurement/uom-systems because Torque is already available in https://github.com/unitsofmeasurement/si-units and the only place I could imagine for a quantity type like TemperatureVolume, ComplexVolume, etc. is uom-systems.

[andi-huber]

Please note the distinction: 1 litre of water has different mass depending on temperature (and pressure). But 1 litre understood as volume in physical space does not change with temperature! So there is no such thing as TemperatureVolume. (At least that does not make any sense to me.) To model your use-case consider to work with mass and density of water (or whatever material you are interested in) and derive the volume from that.

[keilw]

Thanks, then I think we can close that becasue Torque is already defined. Everyone feel free to open another ticket if you feel a quantity or something else was mising.