NERC DataGrid Vocabulary Server

The NDG Vocabulary Server provides access to lists of standardised terms that cover a broad spectrum of disciplines of relevance to the oceanographic and wider community. This includes vocabularies for data mark-up, data categorisation, intrumentation types, named sea areas and many more. The service has a growing community of users including the SeaDataNet project (comprising members from 47 European and North African groups), the British Antarctic Survey and the NERC DataGrid project (with members from a number of UK oceanographic and atmospheric institutions).

Using standardised sets of terms (otherwise known as "controlled vocabularies") in metadata and to label data 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.

An example of how computers may benefit from the use of controlled vocabularies is in the summing of values taken from different data sets. For instance, one data set may have a column labelled "Temperature of the water column" and another might have "water temperature" or even "temperature". To the human eye, the similarity is obvious but a computer would not be able to interpret these as the same thing unless all the possible options were hard coded into its software. If data are marked up with the same terms, this problem is resolved.

In the real world, it is not always possible or agreeable for data providers to use the same terms. In such cases, controlled vocabularies can be used as a medium to which data centres can map their equivalent terms.

The controlled vocabularies delivered by the NDG vocabulary server contain the following information for each term:

• Key - a compact permanent identifier for the term designed for computer storage rather than human readability
• Term - the text string representing the term in human-readable form
• Abbreviation - a concise text string representing the term in human-readable form where space is limited
• Definition - a full description of what is meant by the term

The scope of this service is in constant review as BODC looks to add new methods for retrieving information and new controlled vocabulary lists. All of the vocabularies are fully versioned and a permanent record is kept of all changes made.