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GeoBlacklight is an open-source Ruby on Rails software application for discovering geospatial content, including GIS datasets, web services, and digitized paper maps. Based on the open source software project Blacklight, GeoBlacklight began in 2014 as a collaboration by MIT, Princeton, and Stanford. As of 2021, over 25 academic libraries and cultural heritage institutions have adopted GeoBlacklight.

Discovery services and metadata are key challenges for organizations who provide geospatial data. GeoBlacklight connects expertise from the digital library and geospatial communities to provide a better experience for users to find geospatial data.

Our Community

Participants in the GeoBlacklight community come from a variety of professional and intellectual backgrounds (including librarians, software developers, metadata specialists, applied researchers, and others), but we share a common interest in making reliable and high-quality geospatial data easily accessible to members of the research community and the broader public. Many of us work in libraries and other cultural heritage institutions that deploy (or are planning to deploy) GeoBlacklight instances to disseminate and publicize their spatial data collections.

Anyone interested in spatial data infrastructures, libraries, GIS, maps, data curation, open source software, and related topics, is welcome to join us. Depending on their skills and interests, participants contribute to the community in any number of ways (for instance, by attending meetings, writing documentation, developing metadata best practices, engaging in outreach, and writing code). Participating in the community is especially beneficial to those who are implementing or maintaining GeoBlacklight as a spatial data discovery interface within their own home institutions.

Visit the Connect page to join our online community.


  • Every month: Zoom meetings to share project updates and to discuss topical issues.

  • 2x per year: Community Sprints are similar to a traditional code sprint but also incorporate activities around documentation, metadata, governance, and more.

  • Annually: Geo4LibCamp is a hands-on meeting to bring together those building repository services for geospatial data. The main focus is to share best-practices, solve common problems, and address technical issues with integrating geospatial data into a repository and associated services.


  • Community Coordinator (Karen Majewicz)

    • facilitates community monthly meetings and sets agendas
    • stages project boards for community sprints and coordinates stand-up meetings
  • Code of Conduct team

Our Development Practices

  • Open source model: GeoBlacklight is an open source software project licensed using the Apache License, version 2.0. Our development practices have been codified in a contribution guide since December 2015 and we use semantic versioning to release the Ruby on Rails engine to RubyGems. Changes are made to the codebase using pull requests to the GitHub source code repository.

  • Connected frameworks: Many of the development practices for the GeoBlacklight project have foundations in other open source software communities. A strategic design decision was made to build on existing pools of expertise in organizations with Blacklight and Samvera rather than build a completely custom system. The project also relies heavily on configuration and extensibility as useful patterns for adopters making customizations.

  • Decision-making: Much of the technical decision-making is driven from the original GeoBlacklight Concept Design document and has been further distilled into our GeoBlacklight Technical Values. Major and minor decisions are made using informal consensus.

  • Testing: GeoBlacklight has Continuous Integration Testing, and tests are expected to be written with code contributions to the project. The project also implements both Ruby and JavaScript style guides to ensure a stylistically similar codebase.

  • Funding: There is no funding model for GeoBlacklight, and most development comes through volunteered or assigned time from contributing organizations. Some projects have received grants or dedicated funds to build their GeoBlacklight applications. Our community also includes private vendors and independent freelancers that have contributed to the project through contracted work.

Application Features

  • Technical Stack: GeoBlacklight is a Ruby on Rails engine designed as a plugin for the popular open source discovery framework, Blacklight. GeoBlacklight has direct software dependencies to Blacklight and Ruby on Rails. It also requires searchable metadata through the Apache Solr project. For production uses, GeoBlacklight installations often require a SQL database such as MySQL, MariaDB, or PostgreSQL. 

  • External service integration: GeoBlacklight provides a discovery layer for content that is oftentimes hosted elsewhere. Rather than try to provide a repository to the data itself and navigate the complexities of different adopters existing systems, GeoBlacklight relies on providing integration for existing datastores and web services. GeoBlacklight does this through providing useful preview, download, and exports of open standards-based services, including Web Mapping Services (WMS), Web Feature Services (WFS), ArcGIS Rest API, and International Image Interoperability Framework (IIIF). There is also support for externally referenced metadata viewing and file download support.

  • Metadata: The GeoBlacklight Metadata Schema has been designed to privilege discovery use cases. Text search, faceted search & refinement, and spatial search & relevancy are among the primary features that the schema enables. Visit OpenGeoMetadata for more information and full documentation. Metadata schema features:

    • based on Dublin Core, with custom elements added for spatial values

    • designed for discovery - to help users find items

    • not designed for complete technical documentation, such as a GIS dataset's processing history

    • includes elements for external links, such as downloads, web services, or supplemental metadata

    • interoperable for the OpenGeoMetadata federated metadata sharing community

GeoBlacklight Technical Values

  • Our core focus is geospatial discovery. This focus initially was limited to discretely catalogued data objects, but has expanded over time to include a wider range of information sources.

  • We emphasize end-user experience, including inclusivity and accessibility in design features.

  • We prioritize stability by semantically versioning our application releases and metadata schemas.

  • We aim for GeoBlacklight to be simple to adopt and easy to maintain. We recognize that many adopters are in the cultural heritage space where metadata and software development resources can be limited.

  • We make GeoBlacklight customizable for common use cases, and extensible to a plugin for a less-common use case.

  • We leverage existing communities. Building on established standards gives us more bandwidth to focus on discovery and developing plugins.

  • Excellent geospatial analysis and mapping tools already exist. Rather than build new ones in GeoBlacklight, we focus on integration with these existing tools.

Connected Projects

The GeoBlacklight software stack consists of several open source software projects which work together to enable a better discovery experience.

GeoBlacklight Contributors

GeoBlacklight has been collaboratively developed by affiliates of the following institutions:

  • Auraria Library
  • Big Ten Academic Alliance
  • Cornell University
  • MIT Libraries
  • Harvard University Library
  • Johns Hopkins University
  • New York University Libraries
  • Princeton University Library
  • Stanford University Libraries
  • University of California San Diego
  • University of California Berkeley
  • University of California Santa Barbara
  • University of Illinois at Urbana-Champaign
  • University of Massachusetts Amherst
  • University of Minnesota Libraries
  • University of Pennsylvania Libraries
  • The University of Texas at Austin
  • University of Wisconsin-Milwaukee

Did we miss your institution? Have a suggestion for this website? Create an issue on the GeoBlacklight Website Github page here.