The ScienceBase Item Core Model describes the metadata elements that make up the core of ScienceBase and apply to every item. Extending this model are ScienceBase Item Extensions that add additional attributes to items based on specific needs. Some extensions are created to accommodate particular metadata standards in use for particular types of items. Others are generated when a new ScienceBase Harvester is established to pull in a particular information source with unique information.
To some extent, extensions are artificial constructs of convenience in that any ScienceBase Item can really have any collection of attributes across any extensions. For instance, there is a Project Status element that applies to both a generic Project extension and the very specific BASIS+ extension used to accommodate information from an internal USGS system that shares data with ScienceBase. It is the same attribute with potentially different values applied under the auspices of two different extensions. The extension construct helps to provide some logical grouping and meaning to item attribution.
The following pages discuss current ScienceBase Item Extensions in some detail, laying out the sbJSON constructs and providing information on any applicable metadata standards or code lists used to inform their attribution.
You may find ScienceBase documentation occasionally that uses the word, facet, to describe what we call extension here. We originally used facet to describe this aspect of the architecture because of the use of that term in the underlying database technology for ScienceBase (MongoDB). However, we adopted the use of ScienceBase Item Extension to describe the concept for clarity with the Search Facet concept discussed elsewhere in the documentation.