Composed Metadata Records

Date	2009/09/01
Contact(s)	Simon Pigot
Last edited	Timestamp
Status	draft, being discussed, in progress, early stage complete
Assigned to release	2.5
Resources	Available for first stage

Overview

For GeoNetwork to become part of an institutional metadata and data management fabric, it must be able to compose metadata from content held in databases external to GeoNetwork. This proposal would add two new components to the kernel and harvester modules of GeoNetwork:

• WFS fragment harvester - a harvester that can import metadata fragments (also known as subtemplates) from an external database with a WFS interface
• XLink resolver and cache - metadata records can then be composed from a skeleton with links to fragments of metadata

Proposal Type

• Type: Core Change
• App: GeoNetwork
• Module: Harvester, Kernel, Data Manager, Jeeves

Links

• Other terms: Metadata fragments are equivalent to subtemplates, a concept which has only ever been partially implemented in GeoNetwork. This proposal intends to implement subtemplates as fragments of metadata harvested from an external database. The idea of composed or componentized metadata and the term itself, appears to be common to many discussions on the net eg. (albeit obliquely) ​http://eww.jot.fm/issues/issue_2007_11/column6.pdf. Another term with similar concepts is "relational" metadata. Although there has been discussion in and around these topics, this proposal appears to be the first to suggest the mechanisms for implementing these concepts in GeoNetwork using fragments harvested from a database with a WFS interface.
• Email discussions:
• Other wiki discussions:

Voting History

• Vote proposed by X on Y, result was +/-n (m non-voting members).

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Motivations

The motivation for this proposal comes from the need to fit GeoNetwork into organisations that already manage metadata in a number of different databases external to GeoNetwork.

Proposal

WFS fragment harvester - this is a harvester that accepts (along with the usual harvester parameters) the

Future work would add:

• URN resolver to provide a level of indirection that can be used to cope with changing URLs

Backwards Compatibility Issues

Risks

Participants

• Simon Pigot
• Other XLink implementors: Jesse, Francois, Patrick
• Others?