A guide to Reference index services

Overview

Reference Index services associate information with a canonical identifier. A canonical identifier is either a CTS URN or a Collection identifier. We could describe a reference index mathematically as a relation where information in some domain is mapped to a range of canonical identifiers.

Reference indexing encompasses mappings that we traditionaly call "indices" (such as an index of proper names, an index of geographic names, or a lemmatized index of a text that maps a lemma onto each word of a text), as well as other kinds of mappings: a commentary, for example, could be considered an application relying on an index mapping a potentially complex data structure (the comment) onto a passage of text; a schedule of assigned reading for a class could be considered an application based on an index mapping dates and instructions onto passages of texts. A printed reader aligning passages in the three synoptic gospels could be considered an application mapping parallel themes onto textual references.

Organization of Reference Index Services

An instance of Reference Index Services supports one or more Reference Indexes. The services' indexes are described in an IndexInventory document that is returned by the GetCapabilities request. Information about each index includes a unique identifier and Dublin Core metadata about the index.

Each index is described by an idxstructure element that defines the type of the two parts of the index:

  1. the range of the index, which must be a citation value: a CTS URN, a Collection identifier.
  2. the domain of the index, which can be either a citation value or raw data

All Reference indexes have one or more record elements composed of associated pairs of a ref element from the range of the index, and a value element from the domain of the index.

Requests

Reference Index Services support the following four requests:

    • name of request: GetCapabilities
    • parameters: none
    • returns the IndexInventory document
    • name of request: QueryIndex
    • parameters: IndexID (required); one of ref or value
    • This query method allows you to limit results to matching index values, or to matching citation values.
    • name of request:DownloadIndex
    • parameters: IndexID (required)
    • returns entire index