Ontology

Wikibase implements graph data functionality in a way that does not strictly adhere to OWL (Web Ontology Language) and RDFS (Resource Description Framework Schema), two primary standards for encoding graph data. However, it does implement aspects of these two standards along with others in the following list:

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
@prefix xsd: <http://www.w3.org/2001/XMLSchema#>
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
@prefix owl: <http://www.w3.org/2002/07/owl#>
@prefix skos: <http://www.w3.org/2004/02/skos/core#>
@prefix schema: <http://schema.org/>
@prefix cc: <http://creativecommons.org/ns#>
@prefix geo: <http://www.opengis.net/ont/geosparql#>
@prefix prov: <http://www.w3.org/ns/prov#>

Calling rdfs:label in SPARQL queries results in typical functionality that maps to the primary label used for a property. Using the skos:altLabel predicate will provide aliases for items returned in a query. Using prov:wasDerivedFrom accesses reference triples for a statement.

Other aspects of these standard ontological frameworks are implemented through specific local properties and entities that provide the same functionality. For instance, in the GeoKB, Property:P2 is the property that we use for the owl:subClassOf predicate (same as P279 in Wikidata). A convention we've adopted in the GeoKB is to include a regularly used identifier like "owl:subClassOf" as an alias for property or entity items where we have a specific item that serves that functionality here. We also make use of a same as property (similar to owl:sameAs) to denote cases where a property or entity item should be considered the same (or at least very close to) something from another ontology or source of definition.

The same as designation is a little bit of a tricky designation in that there are often degrees of sameness when we get down to exacting detail. We are exploring conventions on the use of qualifiers to provide details or caveats on any points of disagreement. We have not used references on same as claims as these are essentially a declaration of sameness that is specific to this knowledge representation, basically stating that the user or bot provenance in the history of that claim is directly responsible for the statement.

Same as claims on items in the GeoKB are vitally important connections to other knowledge representations, serving as the linkage, philosophically, between how USGS describes things and how other parties describe those same things. A primary objective in the GeoKB work is to elucidate that mapping wherever we can to help better convey what we know through our scientific research programs in a way that contributes to the abstract idea of the "Global Knowledge Commons" and concrete implementation in places like Wikidata.

Similar to what many other groups are doing, the GeoKB ontology starts at the very abstract level of the Basic Formal Ontology (BFO) with an implicit owl:Thing and a specific entity item as its classification origin. We carry through with the other classes in the BFO to form a core basis for everything else in the GeoKB. We also use select aspects of the Common Core Ontologies (CCO) that apply to GeoKB content (e.g., we do not concern ourselves with familial relationships for persons but we do provide capabilities those persons have as "agents"). As we get deeper into specific knowledge domains, we examine and incorporate domain ontologies, particularly those that already map to the BFO/CCO.

Where we adopt aspects of these ontologies, there is an item in the GeoKB representing that resource as a "knowledgebase source." These are pointed to as "knowledge source" reference statements on claims such as subclass of because we used that ontology to establish an aspect of our classification scheme. The discussion pages on the source items document how we leveraged the source and will show logical queries that will return relevant items from the GeoKB that have same as claims pointing to items within the source.

At the same time, most formal ontologies only represent one overall way of knowing that is particularly slanted toward "western" scientific thought. We are also striving to understand how we connect to other knowledge systems, including work on indigenous knowledge organization, in an attempt to better share and combine knowledge of the earth system. Every time we encounter the need for a new property or class, we look not only to formal ontologies in our scientific domains but to Wikidata (and DBPedia to a lesser extent) to explore where a logical connection can be established. We also record these links as same as statements that may require further examination and clarification with qualifiers through time.