07 August, 2025: The Open Geospatial Consortium (OGC) is seeking public comment on the candidate OGC API – Joins – Part 1: Core Standard. The Standard can be used for online joining of tabular data with other data, such as geospatial datasets. As with relational databases, the join is performed using common key values that are available in both datasets.

The core module specifies requirements for a Web API that supports the following use cases:

  • Getting metadata on available collections, their key fields, and key values.
  • Executing joins between input tabular data files and collections available on external servers.
  • Accessing the created joins.
  • Deleting joins.
  • Executing joins between two input files.

The core module defines three sets of operations: discovery operations, data joining operations, and file joining operations.

Discovery operations specify how to obtain general information about the implementation of a server that supports a join capability. This includes operations for accessing the Joins API landing page, the API definition document, and information on the service’s conformance to the Joins API standard.

Data joining operations provide mechanisms for retrieving metadata, key field information, and key values on the feature collections available on a server. These operations also include functionality to join input data with feature collections as well as to access and delete the resulting joins.

File joining operations specifies an operation for joining data from specified input data files directly with other specified input data files.

The core module specifies requirements for using CSV and GeoJSON input files. The support for other input file formats may be defined in extension modules.

OGC API – Joins addresses many of the same use cases as the OGC Standard: OpenGIS® Georeferenced Table Joining Service (TJS) Implementation Standard (document nr. 10-070r2), specified in 2010. OGC API – Joins, however, offers a modern interface that can be described using the OpenAPI Specification. It is therefore envisioned that many of the statistical authorities and other agencies that implemented the TJS will also consider implementing OGC API – Joins too.

TO COMMENT

The candidate Standard is open for public comment for a period of six months, with comments due by 07 Feb, 2026. Comments can be submitted as an issue on the OGC API – Joins GitHub repository. Comments received will be consolidated and reviewed by OGC members for incorporation into the document.

About OGC

The Open Geospatial Consortium (OGC) is a membership organization dedicated to using the power of geography and technology to solve problems faced by people and the planet. OGC unlocks value and opportunity for its members through Standards, Innovation, and Collaboration. Our membership represents a diverse and active global community drawn from government, industry, academia, international development agencies, research & scientific organizations, civil society, and advocates.

Visit ogc.org for more information about our work.