Name and version: Cristal
Valid: From January 2009
Description: Generic model for complex structuring and restructuring of hierarchical classification structures and classification code systems.
The classification objects such as categories, levels and hierarchies have a property describing their valid periods. The mutual consistency rules for these valid periods are permanently checked.
The model makes it possible for multiple hiërarchical classification structures (trees) to share categories (nodes), levels and hierarchies (subtrees) in many ways.
Intended use: Registration and design of hierarchical classification or code systems and complex relations between them. Reuse of parts of classifications in other classifications.
Reorganization and versioning of hierarchical classifications by introducing changes such as merging en splitting or "jumping" of categories or codes to other branches in the hierarchy.
Design of multiple classifications with mutual overlap.
Maintenance organization: Statistics Netherlands (DSC, data service center)
ISO Standard Number: Not applicable
References: Cristal, a model for the description of statistics, ETK/NTTS, Crete, June 2001.
Cristal, a model for data and metadata, METIS, February 2004.
Relationships to other standards: Concept Map
More generic form of Neuchâtel Model for classifications.
Language: Language independent.
Description last updated / validated: 12 November 2009