bad representation of weight, volume in CargoItem

[VladimirAlexiev]

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

traceability-vocab/docs/openapi/components/schemas/common/CargoItem.yml

Lines 52 to 61 in 8b5efda

	volume:
	title: Volume
	description: >-
	Calculated by multiplying the width, height, and length of the packed
	cargo.
	type: number
	$linkedData:
	term: volume
	'@id': >-
	https://vocabulary.uncefact.org/grossVolumeMeasure

traceability-vocab/docs/openapi/components/schemas/common/CargoItem.yml

Lines 69 to 77 in 8b5efda

	volumeUnit:
	title: Volume Unit
	description: >-
	The unit of measure which can be expressed in either imperial or metric
	terms
	type: string
	$linkedData:
	term: volumeUnit
	'@id': https://schema.org/unitCode

have the following problems:

• Keeping weightUnit, volumeUnit as separate props at the CargoItem level contradicts the discussion/decision in conflated units, weight vs netWeight, xsd:double vs xsd:decimal #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: #532 (comment)

[mkhraisha]

I think our final resolution is to use this layout: #532 (comment)

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