Tips and Tricks

Don’t Have Vocabulary Terms with Embedded Information

Don’t encode information within the vocabulary values. As an example, a value that contains encoded information may have certain characters as meaning certain facts about the value. For example, a single value like XT07aa might indicate an XBT temperature from a T-7 computed using coefficient set aa. Such a value contains information on the type of sensor, the model of sensor, the parameter being measured and processing information. This type of information should be split out of the single value, into multiple values.

Think About Future Grouping of Terms

At some point, you may have to start grouping values associated with the terms in the usage vocabulary; effectively creating a discovery vocabulary. Allowing for such grouping will help in the management of both vocabularies and in the user discovery of terms. Your vocabulary management should be capable of adding this grouping with minimal impact on the management system.

Don’t Allow Users to Manage the Vocabulary

Users need a mechanism to suggest new terms for the vocabulary but they cannot be given the ability to add new terms. A vocabulary is controlled to avoid confusion among terms and to avoid the introduction of errors. Additions, deletions or corrections must be managed by the person responsible for the vocabulary.

Units are Important

Your usage vocabulary may or may not contain explicit units. For example, the data values in the usage vocabulary may have a direct association with the unit (i.e., one term can only have one unit). A preferred method is to allow multiple units for a single data value (e.g., distance can have units of meters or kilometers). By allowing multiple units you effectively introduce another type of vocabulary that your system must support—a unit vocabulary.

The Same Syntactic Rules

The terms used in the vocabulary will be created using a set of syntactic rules that may involve capitalization, the use of underscores, or the use of other special characters. The vocabulary must be developed with consistent application of these rules throughout the vocabulary terms.

Use Natural Terms

Whenever possible, natural terms that are commonly used within the community, should be used within the vocabulary. However, if these terms introduce ambiguity, then consider other terms. Unambiguous terms and definitions are the cornerstone of the vocabulary.

Unambiguous Definition

The terms used in your vocabulary should be associated with rigorous definitions. These definitions should be unambiguous to the community using the vocabulary.

Have a specific question about developing vocabularies? Ask MMI!

Suggested Citation

Isenor, A. 2009. "Tips and Tricks." In The MMI Guides: Navigating the World of Marine Metadata. Accessed July 16, 2020.