Introduction

The other day someone suggested that using the RDL was not essential, and that using other vocabularies is OK in the context of ISO 15926.
I will explain here why he was wrong.

Explanation

In the signature of most Template Specifications you will find PossibleIndividual or ClassOfIndividual. But in real life you will enter an Individual that is typed InanimatePhysicalObject, or Activity, or Person, or Organization, etc. And for ClassOfIndividual a Class that is typed ClassOfInanimatePhysicalObject, or ClassOfActivity, or ClassOfPerson, or ClassOfOrganization, etc.

That is correct, because these are specializations (subclass) of PossibleIndividual or ClassOfIndividual.

A reminder: A Specialization is a Relationship that indicates that all members of the subclass are members of the superclass. Specialization is transitive.

For any other vocabulary, that is not ISO 15926-compliant, that check is not possible.

Some code

In the bottom of the Template Spec "IndividualHasPropertyWithValue" you can find:

GENERIC

:UUID_IN-PTYST-100
      rdf:type tpl:IndividualHasPropertyWithValue ;
      tpl:hasPropertyPossessor "ID"^^dm:PossibleIndividual ; # reference to the ID of a member of PossibleIndividual
      tpl:hasPropertyType "ID"^^dm:ClassOfProperty ;
      tpl:valPropertyValue ""^^xsd:decimal ;
      tpl:hasScale "ID"^^dm:Scale ;
      meta:valEffectiveDate "yyyy-mm-ddThh:mm:ss.sZ"^^xsd:dateTime .

EXAMPLE - Vessel V-101 has a mass of 30.57 Metric Ton

ex:fcbfda39-4d1a-4047-b4ca-45ab8d44fca4
      rdf:type tpl:IndividualHasPropertyWithValue ;
      tpl:hasPropertyPossessor ex:847931fd-eade-4beb-b07d-a9e889611c19 ; # V-101
      tpl:hasPropertyType rdl:RDS353339 ; # MASS
      tpl:valPropertyValue "30.37"^^xsd:decimal ;
      tpl:hasScale rdl:RDS2229868 ; # METRIC TON
      meta:valEffectiveDate "2021-07-27T10:19:00Z"^^xsd:dateTime .

where vessel V-101 is assumed to have been declared as follows:

ex:847931fd-eade-4beb-b07d-a9e889611c19
      rdf:type lci:InanimatePhysicalObject, dm:WholeLifeIndividual, lci:NonActualIndividual, rdl:RDS414674 ;
      rdfs:label "V-101" ;
      meta:valEffectiveDate "2021-07-03T13:53:00Z"^^xsd:dateTime .

where in the lci: extension of the RDL you can find:

InanimatePhysicalObject
id	http://data.15926.org/lci/InanimatePhysicalObject
rdfs:label	InanimatePhysicalObject
rdf:type	Class
rdfs:subClassOf	PhysicalObject

and:

PhysicalObject
id	http://data.15926.org/dm/PhysicalObject
rdfs:label	PhysicalObject
rdf:type	Class
rdfs:subClassOf	PossibleIndividual

Furthermore rdl:RDS353339 - MASS is typed SinglePropertyDimension, which in turn is a specialization of PropertySpace, and that of dm:ClassOfProperty, and rdl:RDS2229868 - METRIC TON is indeed a Scale.

It fits like a Swiss clock, and for the most you don't have to bother about it.