Registry-Related Namespaces
While XML namespace prefixes are by design flexible, there are several namespaces used in registry resource documents that are generally agreed upon within the IVOA. These are each described in the registry extensions section of each descriptive documents in the
IVOA Document Repository. For convenience, a short summary is provided here. The list is primarily populated from the
Registry Table Access Protocol standard document, but also contains retired/deprecated types that may be seen in active registry resources. This list is maintained by the Registry Working Group; please contact the chair or vice-chair if it appears out of date.
Note that documents may or may not reference minor version numbers ahead of a .0 document version. Minor versions of IVOA documents are designed to be backward-compatible in schema within their major version number. Therefore to avoid additional operations/curation effort with each minor document, we do not require registry resources to reference the newest document unless updating to a major version number.
* ssap is the canonical namespace moving forward, not ssa, although ssa is commonly used in registries. "ssa" is used elsewhere regarding utypes.