improvement suggestions for TenneT ontology

[VladimirAlexiev]

I've converted ProTAR TenneT Asset Data SHACL Ontology 2022-12-20 RDFXML0 103038 R2.41.rdf to ttl (will add shortly).
Suggestions for improvement:

• Use consistent URLs. You define a prefix tnt: with hash but then use another URL (with slash) to describe the ontology.
  Instead, define tnt: <http://otl.tennet.eu/tnt/>:

@prefix tnt:    <http://otl.tennet.eu/tnt#> .
<http://otl.tennet.eu/tnt/> rdf:type         owl:Ontology ;

• avoid trailing dots in URLs. These URLs cannot be shortened using the tnt-po: prefix because of the dot:

<http://otl.tennet.eu/tnt/def/po/B.K.B.>
<http://otl.tennet.eu/tnt/def/po/EWF_Energie_Waldeck-Frankenbg.>
<http://otl.tennet.eu/tnt/def/po/Level_stand_1_st.>
<http://otl.tennet.eu/tnt/def/po/Level_stand_2_st.>
<http://otl.tennet.eu/tnt/def/po/Level_stand_3_st.>
...
<http://otl.tennet.eu/tnt/def/po/T.S.I.170.630-11.0.11.>

• each term should have a link to the ontology. You use multiple namespaces, but all terms can link to the same ontology, eg:

tnt-dc:AssetComponentET rdfs:isDefinedBy tnt: .
tnt-et:abbreviation rdfs:isDefinedBy tnt: .

• if possible, avoid GUID URLs for classes and props (use them only for individuals)
• if not possible, use a more appropriate prop (eg dct:relation or rdfs:seeAlso) and a URL not string:

tnt-et:abbreviation  rdf:type  rdf:Property ;
  ## instead of:
  ##     skos:notation       "http://otl.tennet.eu/tnt/def/et/8507342c-c5e3-4f3e-9840-2be205398233" ;
  ## use this:
  rdfs:seeAlso <http://otl.tennet.eu/tnt/def/et/8507342c-c5e3-4f3e-9840-2be205398233>.

• Do not use subPropertyOf just to group properties. Eg you'll get a mix of company codes and budget values in tnt-et:CAT_FinancialAttribute, and how will you tell them apart? Use this criterion: will I ever want to query by the super-property? You already use skos:Collection for grouping, why also use subPropertyOf?

## NOT OK
tnt-et:colour  rdf:type     rdf:Property ;
        rdfs:subPropertyOf  tnt-et:CAT_MechanicalAndDimension .
tnt-et:manufacturedDate
        rdfs:subPropertyOf  tnt-et:CAT_LifeCycleData ;
tnt-et:companyCode  rdf:type  rdf:Property ;
        rdfs:subPropertyOf  tnt-et:CAT_FinancialAttribute.
tnt-et:budget  rdf:type  rdf:Property ;
        rdfs:subPropertyOf  tnt-et:CAT_FinancialAttribute.

## This is OK
tnt-dc:AssetComponentET
        rdf:type         skos:Collection ;
        skos:member      tnt-et:manufacturedDate .  # this would infer that tnt-et:manufacturedDate is a skos:Concept, but that's not a problem
- Use `rdfs:seeAlso` only with URLs, and use `xsd:anyURI` only for literals that are valid URLs or URIs. Use `skos:notation` for tags
```ttl
# NOT OK
tnt-et:maintenancePlant
        rdfs:seeAlso        "TAG0026"^^xsd:anyURI ;
tnt-et:manufacturedDate
        rdfs:seeAlso        "CIM::LifecycleDate / TAG0025"^^xsd:anyURI ;

tnt-et:maintenancePlant
        skos:notation        "TAG0026";
tnt-et:manufacturedDate
        skos:notation        "CIM::LifecycleDate / TAG0025";

• you can even introduce your own datatypes to indicate the tag system, eg

tnt-dt:tag a rdfs:Datatype; rdfs:label "TenneT tags".
tnt-dt:cimTag a rdfs:Datatype; rdfs:label "CIM tags".
tnt-dt:cimDateTag a rdfs:Datatype; rdfs:label "CIM Lifecycle Date tags".
# and then
tnt-et:maintenancePlant
        skos:notation        "TAG0026"^^tnt-dt:tag;
tnt-et:manufacturedDate
        skos:notation        "TAG0025"^^tnt-dt:cimDateTag;

• use only QUDT for unit-related info, not "proxy" classes and props, eg

tnt-pl:QUDTKind_InductanceQuantity ## why not the respective QUDT class?
tnt-et:unit  ## why not qudt:unit?
bs:unit  ## why not qudt:unit?
bs:quantityKind  ## why not qudt:quantityKind ?

Cheers!