This document provides a justification to the OGC Technical Committee (TC) for consideration of STAC as a Community standard. This justification, along with the submitted candidate Community standard, will form the basis for TC review and vote to approve the start of a Work Item as the first step in the Community standard process for this standard.

The submitters agree to abide by the TC Policies and Procedures and OGC Intellectual Property Rights Policy (http://www.opengeospatial.org/ogc/policies) during the processing of this submission.

Once approved, the Community standard Work Item defined by this document is valid for six (6) months.

The SpatioTemporal Asset Catalog (STAC) is an open specification designed to improve the discovery, accessibility, and interoperability of geospatial data. Work on STAC consists of two efforts: A static implementation and a dynamic implementation. The difference is the ability to respond to user queries.

The STAC specification is designed to support geospatial interoperability requirements by providing a common metadata framework to expose geospatial assets, such as satellite imagery and other spatiotemporal raster data. Interoperability eases the search process and enables users to find and use data in various formats and from multiple providers.

The STAC specification evolved from different organizations' collaborative efforts to increase the interoperability of searching for and using satellite imagery. STAC development was driven by the need to overcome the challenges associated with different tools, APIs, and data formats provided for and used in the geospatial community.

The primary STAC use case is to simplify the process of finding and using geospatial assets. It is beneficial for data providers, developers, and data users. Providers can more easily expose their data to the world, developers have a standardized way to interact with geospatial data, and users can more easily find and ingest the data they need.

The STAC community provides various free and open tools and resources to foster uptake and use of the STAC specification. These include a browser for accessing STAC-compliant catalogs and a STAC-compliant Web API for searching and serving metadata for geospatial data.

A comprehensive Best Practices document was created to assist users and developers of the specification. This document captures ideas for working with the specification in specific scenarios - for example, creating a media type to describe a new geospatial dataset or versioning a dynamic STAC catalog.

The STAC specification implements and extends the OGC API – Features standard, and many datasets have been described using the specification. STAC and OGC API – Features evolved together and continually aligned based on user feedback and new implementations.

In addition to the OGC API - Features, the STAC dynamic catalogs align well with the OGC API - Records. Multiple development sprints have been completed with OGC members to ensure alignment between STAC and the OGC Standards baseline.

STAC Collections also aligns with OpenSearch standards for sharing search queries and results via the OGC API - Features standard.

The STAC standard fits well within the OGC API roadmap and aligns with the OGC Features API. STAC also attempts to align with OGC Records API

This specification enhances OGC operations and community involvement by describing geospatial data to newer, non-geospatial companies

The following is a list of publically available implementations of the STAC specification

Planet Labs - https://www.planet.com/data/stac/catalog.json Sparkgeo - https://spot-canada-ortho.s3.amazonaws.com/catalog.json Polar Geospatial Center Data Catalog - https://pgc-opendata-dems.s3.us-west-2.amazonaws.com/pgc-data-stac.json Meteorological Service of Canada (MSC) and Environment and Climate Change Canada (ECCC) - https://api.weather.gc.ca/stac/?f=json USGS 3DEP Lidar data - https://usgs-lidar-stac.s3-us-west-2.amazonaws.com/ept/catalog.json USGS Landsat - https://www.usgs.gov/node/28686

Date of most recent version:

Version 1.0.0 of the STAC Spec was released on May 25, 2021

Implementation description:

Current implementations exist as both static and dynamic STAC. However, this Work Item Justification document only references the static specification, which is the term “stac-spec”. The core JSON documents and link structures are encoded in the specification files and work as long as things are structured properly. A static catalog is crawled by search engines and active catalogs and cannot respond to queries. However, static implementations are very reliable, as there are no servers, no clusters, or databases to maintain. STAC aims to expose as much asset metadata online as possible. As such the static catalog offers a very low barrier to entry for anyone with geospatial assets to make their data searchable. The STAC specification fits well within the OGC API roadmap and aligns with the OGC API - Features. STAC also attempts to align with OGC API – Records.

This specification enhances OGC operations and community involvement by describing geospatial data to newer, non-geospatial parties.

Implementation URL: https://www.stacspec.com

Is implementation complete?

If not, what portions of the proposed Community standard are implemented?

Is the proposed Community standard currently publicly available?

URL: https://www.stacspec.com

Sparkgeo Element84 Planet Labs Microsoft WWU Münster EURAC

Will the contributor retain intellectual property rights?

If yes, the contributor will be required to work with OGC staff to properly attribute the submitter’s intellectual property rights.

If no, the contributor will assign intellectual property rights to the OGC.