Incubating

Incubating — STAC-GeoParquet Beyond Raster Items¶

Status: Maturing convention; may become required.

The item mirror for raster collections is now ratified. See Raster § Item mirror.

An item mirror is a STAC-GeoParquet file containing a collection's items. It is not the provenance meaning of mirror used elsewhere in Portolan, where a mirror is a catalog republishing data it did not produce. See Source Provenance.

Raster item mirrors graduated first because existing stac-geoparquet tooling already reads and writes items.parquet, and because raster scene collections benefit most from avoiding large numbers of per-item JSON requests.

Two extensions remain incubating.

STAC-GeoParquet Mirrors of Collections¶

An item mirror indexes the items in a single collection. A complementary construct could index the collections in an entire catalog, regardless of whether they contain COGs, vector data, or point clouds. Like items.parquet within a collection, such a file would let clients search every collection in a catalog with a single read. It would also provide the same capability for collection types that do not currently publish item mirrors.

The encoding is still unsettled. Collection extents are ranges rather than footprints, summaries have no standard representation, and no existing tooling reads such a file.

Complete STAC Catalogs in GeoParquet¶

The longer-term goal is a STAC-GeoParquet representation that can reconstruct an entire catalog: catalogs, collections, items, and links stored in a queryable set of Parquet files.

That work belongs upstream in stac-geoparquet. Portolan should adopt the upstream convention once it exists rather than defining its own.