MMI Guide for Ontology Providers

MMI Guide for Ontology Providers
Marine Metadata Interoperability Project
Version: November 2, 2008

Introduction

When two or more information systems want to exchange information they need to solve interoperability problems, so they are able to connect, send messages to each other, and understand these messages. The vocabularies used in those messages should be formalized so that a computer programs can understand and work with them. When formalized, vocabularies are often referred to as ontologies, concepts collected to describe a subject matter.

One of the formalizations used to encode controlled vocabularies so that computer programs can better understand each other is the Resource Description Framework (RDF) [8]. The Resource Description Framework is an approach that lets different resources, or their web representations, be related to each other, using still other resources. These related resources are known consist of a subject and object, linked by a predicate.

RDF is composed of resources which are uniquely identified by a Uniform Resource Identifier (URI) [3]. A URI is a web naming/addressing technology that uses short strings to refer to resources in the web. One of the problems of formalizing vocabularies in RDF is defining the structure of the URI string. For example a URI could be a Uniform Resource Name (URN) or a Uniform Resource Locator (URL), and the URI string could contain or omit version or other semantic information.

Some communities, like the Open Geospatial Consortium (OGC), have defined rules to construct URIs for use in their domain specific applications (e.g., OGC's Geographic Markup Language or GML). So far, however, there is little guidance available to the marine information community describing how to create URIs.

This document tries to address this issue, by defining a URI encoding convention for marine-related vocabularies. This document also provides strategies to successfully publish your ontologies. Moreover, this document will serve as the basis to identify resources when creating ontologies, as well as a publishing strategy that will be followed by the Marine Metadata Interoperability (MMI) project.

Notes About this Document

This document has been written by the Marine Metadata Interoperability project, both to document its understanding of best practices for review and reuse by others, and to guide its own development of an ontology repository. Because of said development, we are in the position of implementing solutions even if the best practice in those areas have not been finalized.

Accordingly, we eagerly accept comments on any of this material. We will do our best to update it according to our understanding, and align it with the ontology repository implementation.

You can see the time of significant updates to each subsection of this document by looking at the bottom of the page.