A custom ontology and a custom scheme is where you refine your existing data model using OWL (Web Ontology Language).
A custom ontology is the conceptual representation of the concepts, their attributes and the relations between them in PoolParty. It also defines the underlying data model for a PoolParty project. This is where to organise your data, to improve the search and to integrate this data. To apply this data model to a PoolParty thesaurus, you need to create a custom scheme based on your custom ontology or a predefined ontology and synchronize it.
A predefined ontology has a set of classes, relations and attributes for a specific domain. You can use them on their own or as part of a new custom ontology.
A custom scheme is a container that holds one custom ontology or a predefined ontology. A custom scheme can have elements from different ontologies where these ontology elements can be brought together and applied to your PoolParty data.