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SeaDataNet2>Standards & Software>Common Vocabularies

Common Vocabularies

Use of common vocabularies in all metadatabases and data formats is an important prerequisite towards consistency and interoperability. Common vocabularies consist of lists of standardised terms that cover a broad spectrum of disciplines of relevance to the oceanographic and wider community. Using standardised sets of terms solves the problem of ambiguities associated with data markup and also enables records to be interpreted by computers. This opens up data sets to a whole world of possibilities for computer aided manipulation, distribution and long term reuse.

Therefore common vocabularies were set-up and populated by SeaDataNet. Vocabulary technical governance is based on the NERC DataGrid (NDG) Vocabulary Server Web Service API. Non-programmatic access is provided to end-users by a client interface for searching, browsing and CSV-format export of selected entries. The API is compliant to WS Basis Profile 1.1, which is adopted as standard for all Web Services in SeaDataNet. The Vocabulary Server is populated with lists describing a wide range of entities relevant to marine metadata and data such as parameters, sea area names, platform classes, instrument types, and so on.

Content governance

Content governance of the vocabularies is very important and is done by a combined SeaDataNet and MarineXML Vocabulary Content Governance Group (SeaVoX), moderated by BODC , and including experts from SeaDataNet, MMI, MOTIIVE, JCOMMOPS and more international groups. SeaVox discussions are based on an e-mail list server.

NVS2.0

The NERC Vocabulary Server (NVS) was originally developed in 2006. In order to support the requirements of the user community, several enhancements were required to the existing NVS, and therefore a version 2.0 (NVS2.0) was developed.  

The major upgrades of NVS2.0 consist of:

  • a move to the latest version of the World Wide Web Consortium’s (W3C) Simple Knowledge Organization System (SKOS) specification for encoding the data dictionaries and taxonomies served through the NVS
  • the ability to serve multilingual titles and definitions for resources
  • the provision for mappings to external resources enabling the results of ontology extension to be delivered.

NVS2.0 is operational and SeaDataNet is migrating to using NVS 2.0 from October 2013 onwards marking a successful implementation of the 1st Innovation Cycle of the SeaDataNet II project.

In order for the SeaDataNet infrastructure to make the transition to NVS2.0 a mapping of both Uniform Resource Names and Uniform Resource Locators has been made. The content of relevant NVS2.0 vocabularies has also been rendered in an ISO XML Codelist, to assist in the interoperability of the common vocabularies with the Common Data Index (CDI) and Cruise Summary Report (CSR) representation in ISO19139 XML.

In general, an NVS URL looks like:

  • Controlled Vocabulary: http://vocab.ndg.nerc.ac.uk/list/{listid}/{version}
  • Concept: http://vocab.ndg.nerc.ac.uk/term/{listid}/{version}/{termid}

While an NVS2.0 URL follows the following structure:

  • Controlled Vocabulary: http://vocab. nerc.ac.uk/collection/{listid}/{version}/
  • Concept: http://vocab. nerc.ac.uk/collection/{listid}/{version}/{termid}/

Similarly, the NVS URNs are of the pattern:

  • SDN:{listid}:{version}:{termid}

While in NVS2.0 they follow this pattern:

  • SDN:{listid}::{termid}

NVS {listid}s are of four characters, the final of which loosely indicates the status of the concepts, this fourth character is dropped in {listid}s in NVS2.0. In all versions of NVS, the {version} may be set to “current” in order to access the latest version of the controlled vocabulary or concept.

These differences in URLs and URNs implicate that the migration has an impact on all directories and data sets in SeaDataNet. Activities are therefore underway as part of the 1st Innovation Cycle of the SeaDataNet II project to upgrade all formats, tools, procedures and services in the SeaDataNet infrastructure towards using NVS2.0.  

NVS 1

NVS V1 vocabulary should not be used anymore from October 2013 in the SeaDataNet project. However the service is still maintained for some more months and can be consulted at:

Query the NVS V1 Common Vocabularies via the client interface