Feature Source, Feature, Feature Schema, Class Definition, and Properties
A feature source contains features. A feature consists of a geometry and other information such as unique identifier and a description.
The structure of a feature is modeled as a class and the feature itself as an object. The class contains a default geometry property definition and other property definitions, which may include a non-default geometry property definition. A feature object contains properties, which are instantiations of the property definitions.
A set of related classes are grouped together as a schema. A feature source may contain multiple schema.