NASA Taxonomy - XML DTDs for Use with the NASA Taxonomy

Important Update Regarding the XML format of the NASA Taxonomy - Jan 9, 2007

The next version of the NASA taxonomy will be in the SKOS format.

The SKOS Core is a model and an RDF vocabulary proposed by the W3C for expressing the basic structure and content of concept schemes such as thesauri, classification schemes, subject heading lists, taxonomies, other types of controlled vocabulary.

The SKOS Core Vocabulary is an application of the Resource Description Framework (RDF), that can be used to express a concept scheme as an RDF graph. Using RDF allows data to be linked to and/or merged with other data, enabling data sources to be distributed across the web, but still be meaningfully composed and integrated.

If you are currently using the NASA taxonomy in its previous PRISM format (PCV), please contact us for help with updating your schema.

This page provides XML files containing the NASA Taxonomy. It also links to two XML DTDs (Document Type Definitions) for use with the NASA Taxonomy. One DTD defines the simple XML format for the taxonomy files. The other defines a basic format for metadata which uses the taxonomy. That format is known as the NASA Taxonomy Metadata Recommendation.

pcv_taxonomy_format.dtd - DTD for Vocabulary Files
This is a DTD for a simple, RDF-compliant, taxonomy file format. The taxonomies from the NASA Taxonomy project are provided in this format. Most of the elements in this format come from the PCV (PRISM Controlled Vocabulary) namespace, which is an XML standard developed in the publishing industry. (See www.prismstandard.org for more information on PRISM and PCV). This format is fine for simply sending vocabularies between systems, but it is inadequate for the ongoing maintenance of the vocabularies since it does not provide fields for the 'status' of a taxonomy term, for who entered it, for when it was approved, etc.

nasa_rdf_metadata.dtd - DTD for Metadata Files
This is a simple DTD for an RDF-compliant metadata format. This format is not an offical NASA standard. Instead, it is a recommendation from the NASA Taxonomy Project on what a NASA standard metadata format might look like. The members of the Taxonomy Project recognize that other projects and Centers will have their own formats, and hopes for a dialog in order to come up with an official NASA standard. The format began with the Dublin Core Specification, added some of the Dublin Core extensions, and added new elements in a NASA namespace for fields whose values come from the NASA Taxonomy.

Vocabulary Files

These files contain the NASA Taxonomy. Each facet is in a separate file. The files conform to the PCV_Taxonomy_Format DTD described above.

nasaud2.pcv	Audiences
nasaloc2.pcv	Locations (for the dc:coverage element)
nasorg2.pcv	Organizations (for the dc:publisher element)
nasbus.pcv	Business Purposes
nasinst2.pcv	Instruments
nastype3.pcv	Content Types (dc:type element)
comps.pcv	Competencies
naics.pcv	Industry Sectors
projs.pcv	Missions and Projects
subjs.pcv	Subjects