Registering and Accessing Your Ontology

Once you have your ontology in hand, you need to tell the world about it. You also need a way for the world to easily access your information.

Registering an Ontology

Broadly, there are four modes in which you can register an ontology: submitting it to a central repository, where it is stored and served; registering it in a central repository, which may thoroughly index or even cache it; registering it in an ontology search engine, which will index certain metadata about it, but will not store the original ontology for you; and registering it in regular Web search engines, which index it and make it available without caring that it is an ontology. Each has advantages.

Submitting to a central repository

If you submit your ontology to an effective central repository, this may avoid other steps. The repository should make your ontology visible on the Web as an OWL file, and may even register it with other search engines. The submission also enables the repository to perform other operations like versioning. Of course, this is only effective if all your versions are submitted!

Registering in a central ontology registry

You may want to just register your ontology with a central registry so that the registry can index it and knows about it, while not actually serving your ontology. This is useful if you want the URIs for the terms in your ontology to be in your own namespace, and you want to provide dereferencing (Web responses) for those URIs yourself.

Some registries may perform more advanced indexing and computations with your ontology, making them closer in function to a central repository. However, they will still not be able to provide resolution (dereferencing) services for term URLs that are in your domain.

While some registries may revisit the ontology every so often to see if it has changed, you should confirm this, and consider re-registering the ontology each time it changes.

Registering in an ontology search engine

There may be little distinction between some ontology search engines and ontology registries because these capabilities are still evolving on the Web. As used here, the difference is that a central registry provides more advanced services than simply the ability to find information from the ontology.

An ontology search engine will index your ontology, understanding its ontological components, much like a registry. It might also cache your ontology, but not as a primary service. Compare this to the Web search engine, described below.

The best reason to register with an ontology search engine is that it is dedicated to your particular domain, e.g., environmental science or volcanology.

Ontology search engines may be aware of some ontologies that are not available via the Web and may provide additional categorization functions that are specific to ontologies when compared to regular search engines.

Registering with a Web search engine

Most Web search engines support registration of files or websites. One advantage of registering your ontology with Web search engines is that it becomes visible to the widest possible community. At the same time, anyone who wants to search for terms in ontologies can limit their searches to files ending in .owl, in those search engines that support this kind of advanced search.

If you publish multiple ontologies, some of which may not be linked by other websites, it will be especially important to directly register each ontology with Web search engines.

Enabling Access to your Ontology

Once your ontology is known to the Web, how can people and machines access it? This involves two different sets of customers: those using Web browsers, and those using semantic tools. The former wants to see nicely formatted HTML, while the latter wants to see XML in the form of RDF. Obviously you will have to have a Web server of some sort in place, providing the HTML and the RDF responses.

Some basic information on serving your ontology, for example useful naming conventions, is offered in the Guide for Ontology Providers. The page on Constructing URIs for Ontologies is expecially relevant. More advanced information about serving RDF, even at the same URL as the HTML, is provided by the World Wide Web Consortium (W3C) in its Best Practice Recipes for Publishing RDF Vocabularies. This document contains advice for a wide range of web server configurations. Both of these documents are recommended reading if you are going to have to deal with ontology publication on a regular basis. And if this is just an occasional activity, by all means consider using an ontology repository to take care of the details for you.

Suggested Citation

Graybeal, J. 2011. "Registering and Accessing Your Ontology." In The MMI Guides: Navigating the World of Marine Metadata. Accessed July 9, 2020.