Overview to Choosing and Implementing Established Controlled Vocabularies
There are two ways to obtain a controlled vocabulary: start with an existing vocabulary or build your own. We strongly recommend the first approach for most situations. There are four steps in creating a system with integrated controlled vocabulariesA managed list of terms. In the context of vocabularies, management typically includes careful selection of terms, maintenance of terms over time (i.e. addition, deprecation, modification), and presentation of the vocabulary in an accessible format. Related Guide. (If you have implemented your own vocabulary, you can apply steps three and four after your new controlled vocabulary is established.)
1. Choose a Controlled Vocabulary
Although just a few years ago there were very few mature controlled vocabularies for marine science concepts, today there are many possible candidates to consider. The process of finding suitable candidates, evaluating them, and deciding on the best one is described in the guide Choosing a Controlled Vocabulary.
2. Implement Controlled Vocabularies in Your System
The controlled vocabulary you choose must be integrated into your system. Basic implementation may involve creating and populating a drop-down menu. Because most vocabularies will change over time, keeping your system current will require some strategic decisions and planning for the future. For more information, see the guide Implementing Controlled Vocabularies in Your System.
3. Map Among Controlled Vocabularies
To ensure that your data will be discoverable and understandable outside your project, you may wish to map relationshipsConnections between metadata terms within a vocabulary. These relationships can connect terms by scope, provenance, or other well-defined criteria. between relevant vocabularies. Users of some systems may need to understand which terms in your controlled vocabulary correspond to terms in a different controlled vocabulary, or they may wish to interface with your system using their own terms. In these cases, you may need to create a map between two or more different vocabularies. The guide Mapping Among Controlled Vocabularies describes this process and the available tools.
4. Achieving Semantic Interoperability
Making your data and metadataData about data. Metadata provides a context for research findings, ideally in a machine-readable format. It enables discovery of data via an electronic interface, and correct use and attribution of findings. Related Guide usable in the future, across systems and domains, is the essence of semantic interoperability. This demands use of a consistent semantic frameworkA semantic framework guides a specific development to make use of computer-interpretable programming languages, such as XML, to create systems which promote and allow semantic interoperability. Both semantic interoperability and the Semantic Web rely on the backbone of a semantic framework. May also refer to the Marine Metadata Interoperability's own Semantic Framework. Related Guide that incorporates precision in data entry, naming of variables, and scoping of metadata descriptions so that computer systems—and ultimately the human user—can make use of your terms and your data. We address this topic in the guide Achieving Semantic Interoperability.
The Big Picture
Vocabularies are in their infancy. Patterns for adopting, using, and maintaining vocabularies in data systems are not uniformly followed. Mappings are relatively new and immature, and end-to-end solutions that achieve semantic interoperability are few. Nonetheless, these four steps are essential for good practices when using an established controlled vocabulary.
We encourage you to help us reference the best practices and examples in this fieldIndividual instance of a metadata label and value pair. For example, "creator: John Doe" is a metadata element. Related Guide and to help us describe the processes that provide the best results.