CG-URIs and what they identify

Each resource in culturegraph produces the following URIs:

The CG-URN

The most important identifier is the so-called Culturegraph-URN (CG-URN). The CG-URN is based on the EKI or some other widely deployed (library) identifier schema, e. g. GW, VD16, VD17, LCCN, or OCLC-Number that is attached - with or wihout a prefix - to urn:nbn:de:eki-.

The CG-URN always identifies a bibliographic resource. It does not identify a bibliographic description. If the identifier the CG-URN is based on identifiers for a bibliographic resource – e.g. VD16 – then they identify the same resource. If, however, the identifier the CG-URN is based on identifiers for a bibliographic description – e. g. OCLC-Number – then the CG-URN still describes the bibliographic resource and does not identify the same thing as the identifier it's based on.
For a list of widely deployed identifier schemes, cf. Identifikation der Ressource oder des Datensatzes?

Example: The EKI GBVNLM003525147 is a common identifier for bibliographic records that describe the electronic publication " Society and individual in Renaissance Florence / Max Haller (2003)". The derived CG-URN urn:nbn:de:GBVNLM003525147 will identify the publication itself.

The CG HTTP-URI

This identifier is for use in e. g. LinkedData, where we need a protocol-based URI that can be dereferenced: this is the CG HTTP-URI. The HTTP-URI is based on the CG-URN and is constructed by adding the CG-URN to a specified prefix, e. g. (1) http://culturegraph.org/ or (2) http://culturegraph.org/resource/ . Similar to the CG-URN, the CG HTTP-URI identifies a bibliographic resource. If cg:a-urn is a CG-URN and cg:http-URI is an HTTP-URI based on that URN, we always have cg:a-urn owl:sameAs cg:http-URI.

Example: The bibliographic resource identified by the CG-URN urn:nbn:de:eki-GBVNLM003525147 is equally identified by the CG HTTP-URI http://culturegraph.org/resource/urn:nbn:de:eki-GBVNLM003525147 (or similar as we haven't agreed upon a HTTP-URI scheme yet).

The CG Description-URI

The CG Description-URI is a protocol-based URI that identifies and dereferences to the description of a bibliographic resource. The CG Description-URI for a particular resource is constructed either by adding /about to a CG HTTP-URI version (1) making it http://culturegraph.org/CG-URN/about, or by replacing /resource/ in a CG HTTP-URI version (2) making it http://culturegraph.org/data/CG-URN. Since the CG-Description-URI identifies the description of a bibliographic resource it never refers to the same thing as the CG-URN or the CG HTTP-URI.

Example: The bibliographic resource which is identified by the CG-URN urn:nbn:de:GBVNLM003525147 and the CG HTTP-URI http://culturegraph.org/resource/urn:nbn:de:eki-GBVNLM003525147 (or similar) has a description in culturegraph.org. This description is identified by the CG Description-URI http://culturegraph.org/data/urn:nbn:de:eki-GBVNLM003525147 (or similar).