Cross-Catalogue STAC Search
STAC makes it possible to find geospatial data if you already know what data exists and where to source it from. It’s like the search function on a website. What we’re missing is a search engine that supports pure discovery, finding not just data but also the data sources.
MAAP’s STAC Collection discovery aims to fill this gap. A thin API layer sits between STAC catalogues and a search client. Search queries are routed to a predefined set of STAC catalogues, and individual responses are bundled and returned to the client in one response.
The underlying technology is intentionally simple. Rather than maintaining its own copy of collection metadata, stac-fastapi-collection-discovery forwards each search request to a configurable set of upstream STAC APIs, combines the responses, and returns the results directly to the user. Because the service remains stateless, results always reflect the current state of the upstream catalogs without requiring synchronization or scheduled indexing. The searches are idempotent and are performed in parallel so requests can be processed very quickly.
The service also inspects each upstream STAC API to determine which search capabilities are supported, allowing it to expose only the parameters that are common across the selected catalogs.
The underlying technology is open source so you can roll your own multi-catalogue search. stac-fastapi-collection-discovery implements a STAC-API-compliant API for searching across catalogues; this is the backend. STAC Collection Discovery is the corresponding front-end for exploring search results.