Working roughly off the Indiana University Metadata Standards Universe map, the following questions can be used to organize classes of metadata standards (i.e., what is the purpose of the standard?)
- What do we need to know about an object?
- Identifier standards
- Descriptive metadata
- Rights metadata
- Structural metadata
- Technical metadata
Each also requires knowledge of
- Data dictionaries
- How is that information encoded?
- Record format/markup language
- Metadata Wrappers
- How is that information transmitted and accessed?
This is a gray zone: although not strictly metadata standards per se, many APIs also require that data be encoded in certain markup languages. Transformations come into play here.
- Interchange protocols (Z39.50, HTTP/REST, HTTP/SOAP)
- APIs (CMIS, OAI-PMH, SRU, Atom)