Editing of NCI Thesaurus 20.04d was completed on April 27. 2020.  Version 20.04d
was April's fourth build in our development cycle.

This directory contains files:

	ReadMe.txt			This file
	Thesaurus_20.04d.FLAT.zip	The NCI Thesaurus 20.04d in flat file format
	Thesaurus.FLAT.zip		Same as above but without a version tag
	Thesaurus_20.04d.OWL.zip	The NCI Thesaurus 20.04d in OWL2
	Thesaurus.OWL.zip		Same as above but without a version tag
        ThesaurusInf_20.04d.OWL.zip	The NCI Thesaurus 20.04d, inferred, in OWL2 format


The zip files unpack the following files:

	Thesaurus_20.04d.FLAT.zip	Thesaurus.txt
	Thesaurus.FLAT.zip		Thesaurus.txt
	Thesaurus_20.04d.OWL.zip	Thesaurus.owl
	Thesaurus.OWL.zip		Thesaurus.owl
        ThesaurusInf_20.04d.OWL.zip	ThesaurusInferred.owl

In the first two formats below, the relations are as stated by the editors, no inferred
relations are specified.

The Thesaurus.txt flat file is in tab-delimited format.  Included in this format
are all the terms associated with NCI Thesaurus concepts (names and synonyms), a text
definition of the concept (if one is present), and stated parent-child relations, sufficient
to reconstruct the hierarchy.  The fields are:

	code <tab> concept name <tab> parents <tab> synonyms <tab> definition <tab> display name <tab> concept status <tab> semantic type <EOL>

The "parents" field contains the codes of the superconcept(s).
If a "parents", "synonyms", "display name", or "concept status" field contains multiple entries, these are pipe-delimited.
For root concepts without "parents", this field is empty.  The
first entry in the "synonyms" field is the preferred name of the concept.  If no preferred
name has been stated for the concept, this field contains the concept name.  The "definition"
field contains only one definition if more than one definition is associated with the concept;
not all concepts contain definitions.  A "display_name" or "concept status" may contain zero values.
The "semantic type" field is guaranteed to contain one or more values.

Please see the OWL2_Announcement.txt for details on the changes made to comply with OWL2:
https://evs.nci.nih.gov/ftp1/NCI_Thesaurus/OWL2_Announcement.txt

The Thesaurus.owl file contains the entire terminology expressed in the
Web Ontology Language (OWL), and the rdf:about (rdf:ID) utilizes semantically
meaningless identifiers, e.g. "C123456", which is the value of the "code"
property.  Relations are as stated by the
editors; no inferred relations are specified.  Annotations of use only to the
EVS (for example, editor's notes) are absent in the released terminology.
The rdf:about of annotation and object properties are also replaced with
their corresponding codes.

The unzipped Thesaurus.owl is available directly at http://ncicb.nci.nih.gov/xml/owl/EVS/Thesaurus.owl

The ThesaurusInferred.owl file contains the terminology from the NCI Thesaurus but 
excludes retired concepts and includes inferred relationships. This file is created for 
import into the UMLS and NCI Metathesaurus. Properties of use only to the EVS (e.g. editor 
notes) areabsent in the released terminology.  It also uses semantically meaningless
rdf:about identifiers as described above.

The file nci_code_cui_map_201908.dat contains the map of NCI Thesaurus (NCIt) codes
to NCI Metathesaurus (NCIMeta) CUIs (concept unique identifier).  The format of the
file is code <pipe> CUI <pipe>.  The CUIs are either derived from the UMLS Metathesaurus
(CUIs that begin with "C-digit") or specific to the NCI Metathesaurus (CUIs that begin
with "CL").  This mapping file is created for each release of the NCIMeta, which is
published on a quarterly schedule hence is not current with every release of NCIt which
is published monthly.  Newly created Thesaurus concepts will not appear in this file
until the next release of the Metathesaurus, and newly retired Thesaurus concepts will
continue to appear until the next release of the Metathesaurus.  Archived mapping files
may be found in the archives directory beneath the last release of Thesaurus it was
generated from.  The current mapping file is derived from NCIt version 19.08d and
NCIMeta version 201908.

For previous releases of the NCI Thesaurus please see the archives at
ftp://ftp1.nci.nih.gov/pub/cacore/EVS/NCI_Thesaurus/archive/

For additional information, please see the LexEVS summary page.
(https://wiki.nci.nih.gov/display/EVS/LexEVS+Servers+and+APIs+Summary)