Understanding linked data and linked open data: a guide for art researchers

Akseli Gallen-Kallela, *The Lamenting Boat*, 1906, 43 × 63 cm, tempera on canvas. Image courtesy of the Finnish National Gallery.

Linked data and linked open data (LOD) are transforming how information is structured, accessed, and shared online, and they offer art historians new ways to research, publish, and foster greater collaboration across institutions. This article explains linked data and linked open data, explores their use in digital publications and museums, and discusses why it is helpful for art researchers to understand and adopt linked open data standards.

What is linked data?

Linked data refers to a method of connecting related data across different sources on the web. It requires data to be structured in such a way that it is easily interconnected and understood by machines, which allows for more efficient retrieval and integration of information from various sources.

In the context of art history, linked data allows for the connection of information related to artworks, artists, historical contexts, and more. For example, suppose various institutions have an artist's biographical record, body of work, exhibitions in which their work has been shown, and relevant scholarly articles or books published in a linkable structure. In that case, other researchers can link to that data rather than recreating it themselves. This creates a rich, interconnected web of information that is far more useful than isolated pieces of knowledge.

What is Linked Open Data?

Linked open data (LOD) takes the principles of linked data a step further by ensuring that the data is not only interconnected but also freely available for anyone to access, use, and share. The "open" aspect of LOD refers to the commitment to making data publicly accessible without restrictions. This openness is crucial for fostering collaboration, innovation, and transparency, particularly in the academic and cultural sectors.

For art historians, linked open data means that vast amounts of data about artworks, artists, and historical periods can be freely accessed and integrated into research, digital publications, and educational tools. This promotes a more inclusive and comprehensive understanding of art history, as scholars worldwide can contribute to and benefit from the shared pool of knowledge.

How linked data and linked open data work

Understanding how linked data and LOD work requires a closer look at the process of creating and managing these datasets. The process typically involves the following steps:

Identifying resources: The first step is identifying the resources you want to describe and link. In art history, these resources could include artworks, artists, exhibitions, historical periods, and related entities.
Assigning URIs: Each resource is then assigned a unique URI, which acts as a stable, persistent identifier. This ensures the resource can be referenced unambiguously across different datasets and platforms. (Read more about URIs.)
Creating RDF triples: Relationships between resources are described using RDF triples. For example, you might create a triple that links an artist to their artworks, or a painting to the museum that houses it. (Read more about RDF.)
Using vocabularies and ontologies: Standardized vocabularies and ontologies are important to ensure consistency and interoperability. They provide a common language for describing resources and relationships. Vocabularies like the Getty vocabularies (e.g., the Art & Architecture Thesaurus) are widely used for this purpose.
Publishing the data: The final step is to publish the data on the web with an open license, making it freely accessible for others to use and link to. This can be done using platforms like GitHub, institutional repositories, or dedicated LOD services.

By following these steps, art historians can create linked open data that contributes to a global web of interconnected information, enriching the field of art history and making it more accessible to a wider audience.

Benefits of linked open data in arts research and art institutions

For art historians and others in the digital humanities, understanding and adopting linked open data standards is beneficial for promoting interdisciplinary collaboration, ensuring long-term accessibility and preservation, and enhancing the availability and impact of research.

Promoting interdisciplinary research

Digital art history is inherently interdisciplinary, often involving collaboration between scholars from different fields, such as art history, computer science, data science, and digital media. Linked open data standards provide a common framework that facilitates this collaboration by ensuring that data is structured in a way that can be easily understood and used by different disciplines.

For example, a project that combines art history with digital mapping might use LOD to link artworks with historical maps, enabling researchers to explore the geographical context of artistic movements. By adopting LOD standards, researchers can ensure that their data is interoperable and can be integrated into interdisciplinary research.

Ensuring long-term accessibility and preservation

One of the key challenges in digital art history is ensuring that data remains accessible and usable over the long term. Future access depends on website hosting, program maintenance, and reliable repositories. Linked open data standards help address this challenge by promoting the use of stable, persistent identifiers (such as URIs) and standardized formats (such as RDF). This helps to ensure that data can be easily retrieved, understood, and reused in the future, even as technologies and platforms evolve. This is particularly important for preserving digital research outputs, such as digital catalogues raisonnés, databases, and visualizations. By adopting LOD standards, researchers can work to improve accessibility and relevancy for future scholars.

Enhancing research visibility and reuse

Adopting linked open data standards can also enhance the impact and visibility of research. By making data freely available and interconnected, researchers can reach a wider audience, including other scholars, educators, students, and the general public. Work is more likely to be found, cited, and used by others, increasing its impact and visibility.

This not only increases the visibility of the research but also fosters greater engagement and collaboration. By linking data across different sources and platforms, LOD creates a network of interconnected information that can be easily discovered through search engines, digital libraries, and other online platforms. In this way, the reuse of LOD datasets can lead to new insights and discoveries as researchers build upon and integrate existing data in novel ways.

Supporting ethical data practices

Ethical considerations are central to digital art history and the digital humanities, particularly regarding data management and sharing. LOD standards promote ethical data practices by encouraging transparency, accountability, and responsible data sharing. Researchers can use LOD to ensure that their data is used in ways that respect the rights of individuals, communities, and cultural heritage.

For example, the flexibility of the Getty Vocabularies allows researchers to easily flag outdated language as pejorative and add updated, more accurate terms without erasing institutional history. This approach protects the data's integrity and supports more ethical and inclusive research practices.

Key organizations promoting linked open data in collections and archives

Several prominent arts, library, and archival organizations actively promote linked open data, offering resources, guidelines, and case studies to help institutions and scholars adopt LOD standards. These include:

Getty Research Institute: The Getty provides linked open data for its vocabularies, including the Art & Architecture Thesaurus (AAT) and the Getty Thesaurus of Geographic Names (TGN), making them accessible for research and digital projects.
Europeana: Europeana aggregates cultural heritage data from across Europe and offers extensive resources on using linked open data to enhance the accessibility and interoperability of digital collections.
Digital Public Library of America (DPLA): DPLA supports linked open data initiatives, offering tools and datasets to help institutions create more connected and accessible digital collections.
Library of Congress: The Library of Congress provides guidelines and tools for implementing linked data, including its Bibliographic Framework Initiative (BIBFRAME), which aims to make bibliographic data more accessible and interoperable.
Art Institute of Chicago: The Art Institute of Chicago has made parts of its collection available as linked open data, offering datasets and technical documentation to support scholarly research and digital projects.
The Rijksmuseum (Netherlands) The Rijksmuseum has made significant portions of its collection available as LOD, enabling users and researchers to explore connections between artworks, artists, and broader art movements. They align their data with Europeana and Wikidata to improve accessibility.

These organizations are at the forefront of the movement to make cultural heritage data more accessible and interconnected, providing valuable resources for anyone looking to implement linked open data in the arts and humanities.

Linked data and linked open data in digital publications

Digital publications are a prime example of how linked data and LOD can be used to enhance scholarly work in art history. Traditional print publications are static and limited in scope, whereas digital publications can be dynamic, interactive, and richly interconnected through linked data.

Enhancing content with linked data

Authors can connect their work to a vast web of related resources by integrating linked data into digital publications. For instance, a digital catalogue raisonné might include links to biographical information about artists, metadata about specific artworks, related historical documents, and scholarly articles drawn from various online databases via linked data.

This interconnected approach not only enriches the reader's experience by providing a more comprehensive understanding of the subject but also ensures that the publication remains current. As new data becomes available, it can be automatically linked to the publication, keeping it relevant.

Improving discoverability

Linked data also improves the discoverability of digital publications. When publications are connected to a broader web of linked data, they become more easily searchable and accessible through search engines and digital libraries. This is particularly important for art historians who want their work to reach a wider audience, including scholars, students, and the general public.

Users searching for related topics can more easily find a digital publication linked to data from museum collections, bibliographic databases, and academic repositories. This interconnectedness increases the visibility and impact of the research.

Facilitating collaboration and citation

Incorporating linked data into digital publications also facilitates collaboration among scholars. Researchers can create a more robust and interconnected body of knowledge by linking to and building upon each other's work. Moreover, linked data enables more precise and consistent citation practices, as each referenced resource is uniquely identified and can be easily accessed by others.

A researcher writing about a particular artist might link to related artworks in a museum's online collection, a database of critical essays, and a catalog of past exhibitions. Other scholars can then follow these links to explore the primary sources, build on the original research, and cite it accurately in their own work.

Linked data and linked open data in museums

Museums are among the most significant adopters of linked data and LOD, using these technologies to manage their collections, share information, and engage with the public. The shift toward linked data and LOD is transforming how museums organize their collections and interact with other institutions and audiences.

Collection management and interoperability

Linked data creates more possibilities for museums to manage their collections efficiently by connecting various pieces of information within their own databases and with external sources. For example, linked data could connect an artwork's provenance with its exhibition history, conservation records, and related works in other collections.

This interconnected approach also promotes interoperability between institutions. Museums could use linked data to share information about their collections with other museums, galleries, libraries, and archives, creating a more comprehensive and accessible global network of cultural heritage. This is particularly important for collaborative projects, traveling exhibitions, and research that spans multiple collections.

Enhancing visitor experience

Museums are increasingly using linked data to enhance the visitor experience, both in-person and online. Linked data enables museums to provide richer, more contextualized information about artworks and exhibits. For example, a visitor using a museum's app might scan a QR code next to a painting and instantly access linked data that provides biographical information about the artist, details about the painting's history, and connections to related works in other museums.

Online, linked data can power virtual exhibits, allowing users to explore collections in new ways. For example, a virtual tour of an exhibition might include links to related artworks in other museums, scholarly articles, and multimedia content, all connected through linked data. This creates a more engaging and informative experience for users, whether they are visiting the museum in person or exploring it remotely.

Open access and public engagement

Linked open data plays a crucial role in museums' efforts to make their collections more accessible to the public. By releasing their data as LOD, museums can share their collections with a global audience, enabling researchers, educators, students, and the general public to access and use the data freely.

This openness not only supports scholarly research but also fosters public engagement with cultural heritage. For example, the Rijksmuseum in Amsterdam has made high-resolution images of public domain objects from their collection available as LOD, allowing anyone to explore, download, and use the images for educational, research, or creative purposes. This open access approach democratizes access to cultural heritage and encourages a wider appreciation and understanding of art.

Linked data to promote and protect cultural heritage

Linked data and linked open data are powerful tools that enable the creation of interconnected, accessible, and reusable datasets. LOD enhances research, collaboration, and public engagement, making it an essential component of any digital project.

Adopting LOD standards is not just about keeping up with technological trends; it’s about embracing a new way of thinking about data, research, and cultural heritage. As more institutions and scholars adopt LOD, the potential for new discoveries, insights, and connections grows, opening up exciting possibilities for the future of art history and the digital humanities.