Kataloghierarkier

Kataloghierarkier are hierarchical structures used to organize items within catalogs by grouping them into nested categories. They support navigation, discovery, and retrieval by allowing users to browse from broad topics to more specific ones, or to filter results by attributes such as subject, genre, or author.

A kataloghierarki typically consists of multiple levels connected by parent–child relationships. Each node represents a concept, topic, or attribute and is often labeled using a controlled vocabulary. Top-level nodes form broad categories, while deeper levels provide more specific subcategories. Some catalogs permit polyhierarchy, where a single concept appears under more than one parent, which can aid discovery but complicates navigation and indexing.

Common types include classification hierarchies (for example, the Dewey Decimal Classification and the Library of Congress Classification) that organize materials by subject, and hierarchical thesauri or taxonomies (such as MeSH or LCSH) that define broader/narrower term relationships for indexing. Faceted hierarchies combine multiple axes (subject, author, date) into a navigable tree, often implemented as hierarchical facets in digital catalogs. In practice, kataloghierarkier are implemented in libraries, museums, digital repositories, and e-commerce catalogs to enable browsable navigation and precise filtering.

Implementation typically requires governance of vocabularies, versioning, mappings between schemes, and ongoing quality assurance. Benefits include improved findability and consistency across collections, while challenges include maintaining consistency during updates, handling multilingual contexts, and scaling for large catalogs.