FOAF or schema.org in SAREF ?

• SAREF4CITY uses the Friend Of A Friend vocabulary (FOAF). It declares foaf:Agent and foaf:Person, and defines s4city:Agent that provide and use only public services.
• SAREF4AGRI uses the Friend Of A Friend (FOAF) vocabulary, which is not an OWL ontology. It declares OP foaf:based_near, foaf:member, and classes foaf:Agent and foaf:Person, and hijacks the class foaf:Agent to additionally assert that all values for foaf:member are foaf:Agent. It also uses schema.org vocabulary, which is not an OWL ontology. It declares class schema:Organization as a subclass of foaf:Agent.
• SAREF4EHAW uses the Friend Of A Friend vocabulary (FOAF). It declares foaf:Agent and declares different sub-classes of that class, which are more roles than classes. For example, a person could have the role of a caregiver in some situation, and of a patient in another situation. A ODP for roles should be used instead.
• Both schema:Person and foaf:Person are declared, but foaf:Person is not used. It could be deleted.
• SAREF4WATR reuses the schema.org vocabulary. It declares schema:Person and schema:Organization. Other ontologies use FOAF for these entities. One unique choice should be made for SAREF.

Proposal: avoid FOAF, use schema.org.

correction 1: FOAF is a OWL ontology. schema.org is not. SAREF4AGRI could use foaf:Organization instead of https://schema.org/Organization

correction 2: SAREF4WATR uses the schema.org vocabulary just to describe the author. It's conformant to TS 103673.