Introduction

Information Architecture / Ontology

id	name	unit	object	process ^	process v
I	Syntax	manifestation	file
II	Schema	implementation	encoding	parse	serialize
III	Standard	base	data object	understand	situate
IV	Accessible	abstraction	accessible	abstract	trace
V	Record	entity	aggregate	identify	specify

note: there is a potential one to many relationship in each step from 1-5

lib-re/crosswalk is designed as an experiment in the programmatic realization of the logical separation and inter-relation of the various components of a given metadata set. These flow in a level of abstraction from the particular intricacies of the filetype and syntax to the conceptual or physical entity the metadata seeks to describe.

The first, lowest level of a metadata set is the syntax: the last manifestation of a schema existing as the statically stored data within a given file (e.g. xml and json files each containing Marc 21 metadata). Moving from this lowest level to the next would be parsing - the act of extracting this information from its bits to sensible data. Moving from a higher level back down can be considered serialization, exporting loaded information back out of the program.

The next step, the schema is the functional implementation of a given standard. The schema, like the version number to a given piece of software, is the particular set and arrangement of elements, attributes, and refinements, that constitutes the “the record” as an interpreted informational concrete. The act of going from the schema into a standard, is one of understanding - rooting the specific information in the deductive foundation the standard outlines. Going from a standard into a given schema is to situate it within a given context.

The standard itself is the base informational unit and the most abstract, yet systematically “pure” conception of the existing metadata for a given record. It is represented within the system as the data object which can be implemented freely. To move from the standard to the accessible is to abstract, while moving from the accessible back to the standard is to trace.

The accessible is the interoperable abstraction responsible for the translatability within the system. Comprised of the core, shared elements of the Getty Crosswalk, the accessible is really a series of accessor methods which each standard must implement for itself. To move from the accessible to the aggregate is to identify, collocate, or attach. To move from the aggregate back down to the accessible is to specify.

The aggregate is the representation of the surrogacy of each description for a singular ontological concrete and the abstract record. Allowing for the full interoperability and coordination within the system, it is the thing that fundamentally manages and maintains the logical connection of each “accessible” description coalescing into one object.

It is by this means that I intend to connect metadata not only from different schemas and encodings, but also standards and domains.