Pelagios

Pelagios is a long-running initiative that links information online through common references to places, and more recently through time periods and people. Representing a collaboration of data scientists and humanities scholars, Pelagios has established open methods for linking data, developed tools to support that work, and built a community around its sustainability and further evolution.

Founded in 2010 with ancient world partners, Pleiades, Perseus and Arachne, the initial Pelagios project co-created a lightweight but universally applicable method of linking heterogeneous online materials (texts, images, databases) that are hosted by different global resource providers. This particular Linked Data approach is based on the annotation of place references. Instead of compelling everyone to remodel their data according to a single overarching ontology (such as the CIDOC-CRM), the Pelagios method simply states that each data publisher identifies the places mentioned in their data and then aligns those references to the appropriate record in a global authority of place information — a unique and stable record or Uniform Resource Identifier (URI). By means of annotating place references with gazetteer URIs, resources hosted by different data providers become machine readable, meaning that they are more discoverable, reusable, and interoperable.

The Pelagios method for creating semantic annotations is based on the W3C Web Annotation Data Model. This specification describes a structured model and format to enable annotations to be shared and reused across different hardware and software platforms. In addition, Pelagios Partners have developed the following:

• The Linked Places format, an extension to GeoJSON that provides temporal scoping capability and compatibility with RDF. It is used to describe attestations of places in a standard way, primarily for linking gazetteer datasets;
• The Linked Traces format, an initiative aimed at creating use cases of the W3C Annotation Model. It is used to annotate attestations of historical phenomena with the places relevant to them. It is a supported format in both Recogito and Peripleo (see below).

Between 2013 and 2019, Pelagios was funded by the Andrew W. Mellon Foundation in order to explore the extent to which Pelagios method could be extended to other humanities disciplines. While the Pelagios method for linking data was simple enough for anyone to understand, to actually publish linked data still required technical expertise. To address this challenge and lower the technological barrier to teachers, researchers and curators more generally, Pelagios developed two open-source tools:

• Recogito (2019): an annotation platform for working on texts and images, which enables users to enrich online collections or datasets without the need to learn code, as well as map the places mentioned and link those references to other data on the Web (for more information, see our online tutorial);
• Peripleo (2017): a map-based visualisation prototype, demonstrating the power of linked data and the ability to map the spatial footprint of online collections and documents.

Since 2019, Pelagios has thrived with no core funding as a free and open association of equal and interdependent Partners. This growing community represent a range of work being carried out across the humanities (history, language and literary studies, archaeology, etc.), and cultural heritage (galleries, libraries, archives and museums). Instantiating the principle that linked data is as much (if not more) about linking people, as it is about finding technological solutions, Pelagios continues to develop linked data methods and tools that lower technical barriers and allow humanities and cultural heritage practitioners to work more effectively together in evolving an ecosystem of historical information. While the main business of the Pelagios Network is conducted through regular Activity meetings offering consultancy and support, its social infrastructure addresses the sustainability challenges inherent to dependency on a single source of funding or institutional support, and attempts to avoid reduplication of efforts and resources. In this new model of distributive resilience, the scaffolding afforded by Pelagios's network structure enables individual sources of funding, often very small, to be pooled together to build on existing methods and tools, and meet the evolving needs of the community as a whole. In this way, both Recogito and Peripleo have been re-launched as more modular and customizable tools, while other tools, such as World Historical Gazetteer and PeriodO, have been brought under the aegis of Pelagios, to better address the challenges of sustainability and interoperability across domains and use-cases. It is in this role that Pelagios is currently participating as a partner in the EU-funded ATRIUM project, which is looking to improve access to leading research infrastructures in the Arts and Humanities by enriching metadata in existing catalogues and repositories.