The Open Geospatial Consortium (OGC) is pleased to announce the publication of the SpatioTemporal Asset Catalog (STAC) Community Standards. The STAC family of specifications aims to standardize how geospatial asset metadata are structured and queried. A “spatiotemporal asset” refers to any file that represents information about the Earth at a specific place and time.

Initially designed for satellite imagery, STAC has evolved to support a wide range of data resources and formats, including aircraft and drone imagery; hyperspectral, optical, and synthetic aperture radar (SAR) data; video; point clouds; lidar; digital elevation models (DEM); vector data; machine learning labels; and composites like NDVI and mosaics.

STAC is intentionally designed with a minimal core and a flexible extension mechanism to support a broad set of use cases. Over several years, it has matured into a widely adopted specification used in numerous production deployments.

The standard benefits both data providers and data consumers. Providers can simply use a well-designed, standard format and API without developing proprietary ones, while consumers can rely on existing libraries and tools to access metadata rather than writing new code for each data provider’s proprietary formats and APIs.

The STAC specifications define related JSON object types connected by link relations to support a HATEOAS-style traversable interface and a RESTful API with browse and search capabilities. Typically, several STAC specifications are composed 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 relationships 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.

For more complex querying, such as spatial or temporal predicates, the STAC API can be implemented as a web service to query over groups of STAC objects, typically stored in a database

To the greatest extent possible, STAC uses and extends existing specifications. 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.

“STAC is a widely used specification in the community, and it is exciting to formally include this work as part of OGC”s Standards Baseline. STAC evolved alongside the OGC API suite of Standards and the respective groups worked closely together to ensure alignment amongst the Standards and STAC,” said Scott Simmons, Chief Standards Officer, OGC.

As with all OGC Standards, the OGC SpatioTemporal Asset Catalog (STAC) Community Standards is freely available to download.

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.