bad representation of `weight, volume` in `CargoItem`

[VladimirAlexiev]

@mkhraisha @BenjaminMoe @OR13 @nissimsan Related to #532, these lines

https://github.com/w3c-ccg/traceability-vocab/blob/8b5efda873a477f9f2e2b906c5099fb65363b58a/docs/openapi/components/schemas/common/CargoItem.yml#L52-L61

https://github.com/w3c-ccg/traceability-vocab/blob/8b5efda873a477f9f2e2b906c5099fb65363b58a/docs/openapi/components/schemas/common/CargoItem.yml#L69-L77

have the following problems:

• Keeping weightUnit, volumeUnit as separate props at the CargoItem level contradicts the discussion/decision in #532 to use MeasuredValue or QuantitativeValue: the unit should be inside such nodes
• volume says "Calculated by multiplying the width, height, and length" but there are no fields height, length
• volume is mapped to https://vocabulary.uncefact.org/grossVolumeMeasure but that's a structured node with type https://vocabulary.uncefact.org/MeasureType with fields MeasureTypeCode (unit), MeasureTypeValue (value) wheres the examples show volume to be a decimal.

[OR13]

Please raise a PR.

[VladimirAlexiev]

@OR13 , @mkhraisha Before anyone can make a PR, there must be agreement how to represent measurements

• a simple literal as most of them are?
  • xsd:decimal or xsd:double?
• or an intermediate node that carries value, unit?
  • which class & props to use? I would suggest s:QuantitativeValue: s:value, s:unitCode
  • which UOM system (set of units) to use? I would suggest QUDT, eg unit:M, unit:KiloGM

[nissimsan]

Decision here: https://github.com/w3c-ccg/traceability-vocab/issues/532#issuecomment-1589583220

[mkhraisha]

I think our final resolution is to use this layout: https://github.com/w3c-ccg/traceability-vocab/issues/532#issuecomment-1589583220

i.e we should use xsd:decimal and we should use QuantitativeValue