OpenURL

Key takeaways

OpenURL belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect OpenURL to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of OpenURL from memory before moving on to harder problems.

Reference excerpt

An OpenURL is similar to a web address, but instead of referring to a physical website, it refers to an article, book, patent, or other resource within a website. OpenURLs are similar to permalinks because they are permanently connected to a resource, regardless of which website the resource is connected to. Libraries and other resource centers are the most common place to find OpenURLs because an OpenURL can help Internet users find a copy of a resource that they may otherwise have limited access to. The source that generates an OpenURL is often a bibliographic citation or bibliographic record in a database. Examples of these databases include Ovid Technologies, Web of Science, Chemical Abstracts Service, Modern Language Association and Google Scholar. The National Information Standards Organization (NISO) has developed standards for OpenURL and its data container as American National Standards Institute (ANSI) standard ANSI/NISO Z39.88-2004. OpenURL standards create a clear structure for links that go from information resource databases (sources) to library services (targets). A target is a resource or service that helps satisfy a user's information needs. Examples of targets include full-text repositories, online journals, online library catalogs and other Web resources and services. OpenURL knowledge bases provide links to the appropriate targets available.

History OpenURL was created by Herbert Van de Sompel, a librarian at the University of Ghent, in the late 1990s. His link-server software, SFX, was purchased by the library automation company Ex Libris Group which popularized OpenURL in the information industry. In 2005, a revised version of OpenURL (version 1.0) became ANSI/NISO standard Z39.88-2004, with Van de Sompel's version designated as version 0.1. The new standard provided a framework for describing new formats, as well as defining XML versions of the various formats. In 2006 a research report found some problems affecting the efficiency of OpenURL linking and recommended the creation of a group to establish best practice solutions. The KBART (Knowledge Bases And Related Tools) working group has been set up to progress the recommendations of the research report. OpenURL standards and reporting work continues with NISO's IOTA (Improving OpenURLs Through Analytics) project, which produced a reporting tool and research summary in 2013 noting the benefits of data analysis to improve link resolution. In June 2006, NISO designated the Online Computer Library Center (OCLC) as the "maintenance and registration agency" (or "registry agent") of the OpenURL standard, for an initial term of five years. In 2011, OCLC researchers highlighted their work in a NISO journal article, noting that "the OpenURL standard is one of the most heavily used NISO standards". As registry agent, OCLC was responsible for reviewing proposed extensions to the standard and maintaining a listing of those it approved. Per the standard, registry entries could specify particular metadata fields and their representation. The registry had the canonical URL http://www.openurl.info/registry. In 2022, OCLC updated its OpenURL Registry webpage to state that the registry is no longer supported or maintained, saying it had been an "experimental research project" and "research prototype application". The standard registry URL now redirects to an archived version of the site, described as "the Frozen (deprecated) version of the Registry for the OpenURL Framework".

Standards NISO OpenURL version 0.1 (2000-05-16) NISO OpenURL version 1.0f (2003-03-18) ANSI/NISO Z39.88-2004 ANSI/NISO Z39.88-2004 [R2010]

Use The most common application of OpenURL is to assist in the resolution of a request for a web resource (such as an online article). An OpenURL includes information about the referenced resource itself, and context information — both the context in which the OpenURL occurs (for example, a page of search results from a library catalog) and the context of the request (for example, the particular user making the request). If a different context is expressed in the URL, a different copy ends up resolved to. Changes in context are predictable, and do not require the original creator of the hyperlink (for example, the journal publisher) to handcraft different URLs for different contexts. For example, changing either the base URL or a parameter in the query string can mean that the OpenURL resolves to a copy of a resource in a different library. So the same OpenURL, contained for instance in an electronic journal, can be adjusted by any library to provide access to their own copy of the resource, without completely overwriting the journal's hyperlink. The journal provider, in turn, is no longer required to provide a different version of the journal, with different hyperlinks, for each subscribing library (See also COinS).

Format An OpenURL consists of a base URL, which contains the address of the user's institutional link-server, followed by a query string, consisting of key-value pairs serializing a ContextObject. The ContextObject is most often bibliographic data, but as of version 1.0 OpenURL can also include information about the requester, the resource containing the hyperlink, the type of service required, and so forth. For example:

http://resolver.example.edu/cgi?genre=book&isbn=0836218310&title=The+Far+Side+Gallery+3 is a version 0.1 OpenURL describing a book. http://resolver.example.edu/cgi is the base URL of an example link-server. In version 1.0, this same link becomes somewhat longer:

http://resolver.example.edu/cgi?ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:book&rft.isbn=0836218310&rft.btitle=The+Far+Side+Gallery+3 The above query string consists of the following key-value pairs:

ctx_ver=Z39.88-2004 – specifying the ContextObject version rft_val_fmt=info:ofi/fmt:kev:mtx:book – specifying the metadata format for the referent (in this case, a book) Fields from this format describing the referent object: rft.isbn=0836218310 – the ISBN identifying the book rft.btitle=The+Far+Side+Gallery+3 – the title of the book Keys always consist of safe characters and are not encoded, but values are URL-encoded.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with OpenURL

Start with the simplest possible case. Write down what OpenURL claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to OpenURL before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about OpenURL ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of OpenURL

In research: OpenURL appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses OpenURL in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: OpenURL is common in secondary-school and first-year university syllabi. It links to neighbouring topics Internet architecture, Library automation, Library science, so understanding it makes those chapters shorter.
In everyday life: Look for OpenURL outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study OpenURL in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what OpenURL means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain OpenURL out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is OpenURL in simple terms?

An OpenURL is similar to a web address, but instead of referring to a physical website, it refers to an article, book, patent, or other resource within a website. OpenURLs are similar to permalinks because they are permanently connected to a resource, regardless of which website the resource is con…

Why does OpenURL matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study OpenURL?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on OpenURL.