User:Smiltz/Library classification

Lead
New: A library classification is a system used within a library to organize materials, including books, sound and video recordings, electronic materials, etc., both on shelves and in catalogs and indexes. Each item is typically assigned a call number, which identifies the location of the item within the system. Materials can be arrange by many different factors, typically in either a hierarchical tree structure based on the subject or using a faceted classification system, which allows the assignment of multiple classifications to an object, enabling the classifications to be ordered in many ways.

Current: A library classification is a system of organization of knowledge in which sources are arranged according to the classification scheme and ordered very systematically. Library classifications are a notational system that represents the order of topics in the classification and allows items to be stored in the order of classification. Library classification systems group related materials together, typically arranged as a hierarchical tree structure. A different kind of classification system, called a faceted classification system, is also widely used, which allows the assignment of multiple classifications to an object, enabling the classifications to be ordered in many ways.

Types[edit]
There are many standard systems of library classification in use, and many more have been proposed over the years. However, in general, classification systems can be divided into three types depending on how they are used:


 * Universal schemes
 * Covers all subjects, e.g. the Dewey Decimal Classification (DDC), Universal Decimal Classification (UDC), Library of Congress Classification (LCC), and Colon Classification (CC).


 * Specific classification schemes
 * Covers particular subjects or types of materials, e.g. Iconclass (art), British Catalogue of Music Classification, and Dickinson classification (music), or the NLM Classification (medicine).


 * National schemes
 * Specially created for certain countries, e.g. Swedish library classification system, SAB (Sveriges Allmänna Biblioteksförening).

In terms of functionality, classification systems are often described as:


 * Enumerative
 * Subject headings are listed alphabetically, with numbers assigned to each heading in alphabetical order.


 * Hierarchical
 * Subjects are divided hierarchically, from most general to most specific.


 * Faceted/analytico-synthetic
 * Subjects are divided into mutually exclusive orthogonal facets.

There are few completely enumerative systems or faceted systems; most systems are a blend but favouring one type or the other. The most common classification systems, LCC and DDC, are essentially enumerative, though with some hierarchical and faceted elements (more so for DDC), especially at the broadest and most general level. The first true faceted system was the colon classification of S. R. Ranganathan.