Probably like many of you in the class, my process of learning about the world of metadata has been putting together puzzle pieces to form a big picture. I’m a “big picture” person and find it helpful to come up for air when surrounded by lots of detail (and lots of acronyms) to get an overview of a project.
First to lay out were some of the different metadata schemas—such as Dublin Core, MODS, VRA, CDWA, EAD—and the differences between them including their application in context of community need and required level of granularity. The schemas primarily inform the left side elements. These are the element sets.
Next to consider in piecing it together were the right side values. These can be standard or non-standard. Standard requires controlled vocabularies—such as AAT, LCTGM, LCSH, ULAN. The controlled vocabularies provide guides to choice of terms or words in data values.
Also needed are standards for the organization and formatting of the words in these data values. That’s where data content standards come in. Content standards are guidelines for data input. The CCO is an example of a data content standard.
We keep talking about XML with metadata. How does XML fit in? All of this metadata must be machine-readable. XML provides this aspect by encoding metadata for machine-readability, computer processing, and system exchange. XML needs to be defined by standards or DTDs such as MODS-XML, VRA-XML, or TEI.
This is referred to in the textbook as the fourfold typology of metadata standards:
- Structure (metadata element sets); examples: Dublin Core, VRA, MODS, CDWA, EAD
- Content (data content standards); example: CCO
- Value (data value standards with controlled vocabularies, thesauri); examples: AAT, ULAN, LCTGM
- Encoding and exchange (metadata for machine-readability); example: XML
When establishing the metadata element / value pairs, or statements, for a digital collection, there need to be written guidelines about what elements and values are required for the digital collection metadata and the rules of application. Now add metadata schema design to the picture—also known as metadata guidelines, metadata scheme documentation, best practice guides, or application profiles. We have examples for reference in the Indiana Memory Project DC Metadata Guide and the Access Pennsylvania Digital Repository Guidelines. This is our next step in the class project: creating a written set of guidelines for the application of our chosen elements and the values to be entered.