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.. index:: pair: Taxonomies; Overview

.. _working_with_taxonomies_target:

Working with Taxonomies
-----------------------

The **Taxonomies** collection type supports creating asset collections based on `SKOS`_ (the Simple Knowledge Organization System), the W3C standard ontology designed for representing taxonomies, thesauruses, and subject heading schemes.

EDG taxonomies are SKOS-based collections (i.e. datasets).
When a new taxonomy collection is created, EDG will automatically include the SKOS ontology.
SKOS provides a definition of *Concept* and related classes and their properties e.g., fields like preferred and alternative labels, various notes and relationships.
Other EDG collections do not typically or automatically include SKOS, although they may.

Every taxonomy is expected to have at least one *Concept Scheme* that identifies its “top concepts”.
A taxonomy can have multiple concept schemes; however, a better practice can be to use a single concept scheme per individual taxonomy.
Since taxonomies can, as can all asset collections, be included into each other, a taxonomy with multiple concept schemes can be assembled through inclusion of several single concept scheme taxonomies.

Use of the pre-defined SKOS fields can be configured locally for a given taxonomy, globally for the entire EDG or for a subset of taxonomies e.g., all taxonomies associated with some business area.
You can disable fields for all or a group of taxonomies by taking advantage of the Ontology modeling functionality in EDG - see :ref:`ontologies_collections_target`.

Rules and constraints specified by SKOS are also included by default, as are other common constraints for taxonomies e.g., a concept must have a broader parent or be a top concept of some scheme.
If desired, they can be disabled.

Ontologies are also used to define custom, non-SKOS properties for taxonomy concepts and to define specializations (sub classes of concepts).
If you customize SKOS, make sure that the ontology with your customizations is included in the taxonomies to which the customizations apply.
There is a system-wide setting your EDG administrator can use to ensure that the customized ontology is included in every new taxonomy.
If customization only applies to a subset of taxonomies, creator of a taxonomy collection can use the *Settings, Includes* dialog to include the customized ontology.

.. seealso::

 * Please see the :ref:`asset_collections` for all the general features of asset collections such as import/export, editing, user permissions, reports and settings.



.. include:: ./taxonomy_editor.rst
.. include:: ./taxonomy_concepts_panel.rst
.. include:: ./merging.rst
.. include:: ./cloning_and_replacing.rst
.. include:: ./deleting_assets.rst
.. include:: ./exporting_taxonomies.rst
.. include:: ./skos_xl_taxonomies.rst