Metadata

Schemata

• The Curator Ontology consists of contributions of the Curator project to the base ESG ontology. The majority of contributions relate to model components, grids, and activities. View UML (dated August, 2008)
• The ESG Ontology consists of many classes and properties used to describe datasets. It is constantly evolving. View UML (dated August, 2008)
• The METAFOR's Grid Ontology is a UML version of the Gridspec that originated at GFDL. View UML (dated November, 2008)

Formats

• XML is a markup language to structure information in reusable ways. XML consists of tags, which unlike HTML, is not limited to a set of predefined options. Curators use profiles are written in XML. An XML Schema is written in the Schema Definition Language (XSD) and is used to constrain and define XML. For instance, if there are multiple options for a particular name-value pair, these can be explicitly listed in a XSD document. This XSD document can then be used to validate a particular XML instance. Learn how to create an XML Schema (XSD) document.
• RDF is a means of creating relationships between different pieces of structured information. For instance, a car has a color, which is red. In RDF this would be translated into a triple (object:car, property:color, value:red). RDF is being used by Curator to connect model metadata to itself and to datasets.
• OWL is a web ontology language. It comes in three flavors, and is used in ESG to add the concept of classes and a class hierarchy to the ontology. This facilitates the use of inheritance between classes and subclasses. Additionally, OWL takes the property portion of the RDF triple and allows for the creation of datatype and object type properties. Object type properties point to instances within an OWL class and enable connectivity between complex objects. Datatype properties allow for the creation of free strings.
• UML is a means of visually displaying objects and attributes and relationships between them. The Curator project is using UML as an easy way to share with others the complex ontological relationships of OWL.