macrostrat.raster_index

An index of cloud-optimized rasters (COGs), grouped into named layers that a tile server can serve as single mosaics.

Nothing here stores pixels. A row in raster_layers.raster is a reference to a COG in object storage plus the metadata needed to decide whether reading it is worthwhile for a given tile: its footprint, its native zoom range, and its data type. The schema name is raster_layers rather than raster/rasters to stay clear of PostGIS Raster's vocabulary.

Serving these layers is macrostrat.raster_layers.

Usage

from macrostrat.raster_index import RasterIndex, LayerDefinition

index = RasterIndex("postgresql://localhost:5432/macrostrat")
index.create_schema()  # or apply `schema_files()` through your own system

index.register_layer(
    LayerDefinition(slug="emit-minerals", name="EMIT mineral maps", maxzoom=14)
)
index.add_raster(
    "https://storage.example.org/rasters/nevada.tif", layer="emit-minerals"
)

index.assets_for_tile(x=180, y=411, z=10, layers=["emit-minerals"])

Schema

schema_files() returns the SQL defining the schema, in application order, so a host application can fold it into its own schema management rather than calling create_schema(). Two tables and a few functions:

• raster_layers.layer — a named mosaic, and the defaults its rasters inherit (zoom range, rescale range, colormap).
• raster_layers.raster — one COG: href, EPSG:4326 footprint, zoom range, dtype/nbands/nodata, and the full reader metadata as info.
• raster_layers.get_rasters(x, y, z, layers[]) — asset selection, ordered by layer priority then resolution. The core of the whole package.
• raster_layers.should_generate_tile(...) — whether any asset actually resolves at this zoom, for cache warmers and render short-circuits.
• raster_layers.layer_footprints(layers[]) — footprints as GeoJSON features.

CLI

raster-index reads RASTER_INDEX_DATABASE (or DATABASE_URL):

raster-index define-layer emit-minerals --name "EMIT mineral maps"
raster-index scan https://storage.example.org/remote-sensing-data/emit-mineral-maps/ \
  --layer emit-minerals
raster-index set-colormap emit-minerals --from https://storage.example.org/.../nevada.tif
raster-index assets 10 180 411 --layer emit-minerals

The connection is a parameter of the app itself: --database, or those environment variables. A host application that already knows its own connection (Macrostrat mounts these as macrostrat raster) calls set_default_connection(url_or_callable) once, and its users never pass --database — though it still works, and still wins. Scanning object stores needs the s3 extra (boto3), whichever URL form you use — an https:// bucket URL is rewritten into an endpoint/bucket/prefix and listed through the same S3 API, rather than being a second code path.

Known limitations

• Footprints are bounding boxes, so rasters crossing the antimeridian are indexed incorrectly. The column is typed geometry, not polygon, so a mask-derived footprint can replace them without a migration.
• WebMercatorQuad only. Alternate tile grids (and non-Earth bodies, as in mars-tiler) would need a per-grid bounds table.