Request Open: March 21, 2025 9:00 am — April 21, 2025 11:59 pm (30 days left) (AoE)
The popular SpatioTemporal Asset Catalog (STAC) family of specifications aim to standardize the way geospatial asset metadata is structured and queried.
Contact: info@ogc.org
The Open Geospatial Consortium (OGC) is seeking public comment on the potential adoption of the SpatioTemporal Asset Catalog (STAC) family of specifications, including the STAC API, as OGC Community Standards.
The STAC family of specifications aim to standardize the way geospatial asset metadata is structured and queried. A “spatiotemporal asset” is any file that represents information about the Earth at a certain place and time. While STAC originally focused on scenes of satellite imagery, the specifications now cover a broad variety of uses, including sources such as aircraft and drones, and data such as hyperspectral optical, synthetic aperture radar (SAR), video, point clouds, lidar, digital elevation models (DEM), vector, machine learning labels, and composites, such as mosaics.
STAC is intentionally designed with a minimal core and flexible extension mechanism to support a broad set of use cases. The specification has matured over the past several years and is used in numerous production deployments.
Standardization is advantageous to providers of geospatial data, as they can simply use a well-designed, standard format and API without needing to design their own proprietary one. Likewise, standardization is advantageous to consumers of geospatial data, as they can use existing libraries and tools to access metadata, instead of needing to write new code to interact with each data provider’s proprietary formats and APIs.
Static STAC Catalogs
The STAC specifications define related JSON object types connected by link relations to support a HATEOAS-style traversable interface and a RESTful API providing additional browse and search interfaces. Typically, several STAC specifications are composed together to create an implementation. The Item, Catalog, and Collection specifications define a minimal core of the most frequently used JSON object types. Because of the hierarchical structure between these objects, a STAC catalog can be implemented in a completely ‘static’ manner as a group of hyperlinked Catalog, Collection, and Item URLs, enabling data publishers to expose their data as a browsable set of files. If more complex query abilities are desired, the STAC API specification, which forms part of this Public Comment Period, can be implemented as a web service interface to query over a group of STAC objects, usually held in a database.
A STAC API for Dynamic Catalogs
A STAC API is a dynamic version of a SpatioTemporal Asset Catalog. The STAC API specification and repository defines the three STAC API foundation specifications – STAC API – Core, STAC API – Features, and STAC API – Item Search – which can be composed with Extensions to define a specific STAC API implementation. A STAC API can be used to retrieve STAC Catalog, Collection, Item, or STAC API ItemCollection objects from various endpoints.
The API can be implemented in compliance with the OGC API – Features Standard. In this case STAC API can be thought of as a specialized Features API to search STAC catalogs, where the features returned are STAC Item objects that have common properties, links to their assets, and geometries that represent the footprints of the geospatial assets.
STAC and Existing Standards
To the greatest extent possible, STAC uses and extends existing Standards. The most important object in STAC is an Item, which is simply a GeoJSON Feature with a well-defined set of additional attributes (“foreign members”). The STAC API extends the OGC API – Features – Part 1: Core with additional web service endpoints and object attributes.
The original source for the STAC specification is located on the radiantearth stac-spec GitHub repo.
Providing Feedback
The candidate Spatio Temporal Asset Catalog (STAC) Community Standard (OGC 25-004) (.HTML) and associated candidate STAC API Community Standard (OGC 25-005) (HTML)[SC1] are available for review and comment on the OGC Portal. Note that some relative links in these documents do not resolve, so reviewers are encouraged to go to the STAC sources for the STAC Specification 1.0.0 and STAC API Specification 1.0.0. Comments are due by April 21, 2025 and should be submitted via the method below.
To Comment:
Comments can be submitted to a dedicated email reflector for a period ending on the “Close request date” listed above. Comments received will be consolidated and reviewed by OGC members for incorporation into the document. Please submit your comments via this email address, using this Comments Template for the message body.
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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 broad and active global community drawn from government, industry, academia, international development agencies, research & scientific organizations, civil society, and advocates.
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