= Facet selection and description =

* [[attachment:fassetten.pdf|About facets (in German, includes a definition of facet, search facet, and display facet)]]
* [[attachment:facets.ods|List of facets desired by CLARIN-D centers]]
* [[attachment:VLO_facets.pdf|List of facets with ISO-CAT info (incomplete)]]
* [[attachment:time_coverage.pdf|Time Coverage: Definition, Use Cases, VLO Interface, Data Categories, Components]]

== Exploiting ISOcat data categories ==

Currently (January 2014) the VLO relies on two separate strategies for MD selection to populate its facets:

1. ISOcat DCs associated with a MD field in the underlying CMDI profile
2. a set of centre specific XPaths for CMDI instances to
 * explicitly select MD fields for inclusion in a facet that was not matched by a ISOcat DC (white list)
 * explicitly discard MD fields that were selected via their ISOcat DC (black list)

Ideally, strategy 1 should suffice for proper MD selection for the facets. To fix the current state of the MD instances and the VLO we will have to answer the questions:

1. Does VLO rely on appropriate, i.e. sufficiently concrete defined ISOcat DCs? Obviously DCs like http://www.isocat.org/datcat/DC-2482 (language ID) or http://www.isocat.org/datcat/DC-2484 (language name) are semantically too vague and don't allow for the differentiation between the language a resource is written in or the language of an actor in case of transcribed recordings and so on.
 * Solution: Only use narrowly defined DCs for VLO facets.
 * Task: Evaluate the current mapping of ISOcat DCs to VlO facets
2. Do CMDI profiles use sufficiently concrete ISOcat DCs?
 * Task: Create an overview of the DCs actually used by the centres.
 * Task: Evaluate the whitelist/blackclist XPaths with respect to why they are needed (to select vaguely defined DCs? to select MD fields that don't have a DC associated? anything else?) [[herold|Axel Herold]]: I will prepare such a list.
 * Task: Propose the adoption of container DCs for profiles that rely on vaguely defined DCs