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STAC Specs

This page explains the STAC-facing metadata layer around CoRE Stack outputs, especially for people who want to download ready files with metadata and styling, or load them quickly into QGIS.

CoRE-Stack STAC Browser

The root catalog currently exposes two major branches:

  1. Tehsil for tehsil-scoped collections
  2. Pan-India for pan-India collections

The tehsil-wise catalog currently includes state collections such as bihar, jharkhand, odisha, uttar_pradesh, karnataka, rajasthan, maharashtra, gujarat, andhra_pradesh, assam, chhattisgarh, delhi, goa, haryana, himachal_pradesh, madhya_pradesh, meghalaya, west_bengal, nagaland, tamil_nadu, telangana, and kerala.

The pan-India catalog currently includes collections such as drainage layers, terrain, hydrological boundaries, administrative boundaries, land use land cover, groundwater layers, waterbodies layers, and restoration-oriented datasets.

What A STAC Item Gives You

In practice, a CoRE Stack STAC item can give you everything need for your further workflow:

  • the data file itself, usually GeoTIFF for rasters or GeoJSON/WFS-backed GeoJSON for vectors
  • a QGIS style file such as .qml
  • a thumbnail preview
  • geometry, bbox, and time coverage
  • field-level metadata through table:columns on vector items
  • provider, license, and descriptive metadata

For example, current bihar_nalanda_hilsa_cropping_intensity_vector item includes:

  • a json data asset (shape file) pointing to a GeoServer WFS GeoJSON endpoint
  • a style asset pointing to a QGIS style file in [core-stack-org/QGIS-Styles](https://github.com/core-stack-org/QGIS-Styles) repository.
  • a thumbnail asset
  • table:columns metadata describing many output fields

QGIS Workflow

Tested on Linux with QGIS 3.4+.

Quick setup

  1. Open the STAC browser panel in QGIS
  2. Add a new connection using the root catalog URL
  3. Browse to the state, district, and tehsil or to a pan-India collection
  4. Download the assets you need
  5. Drag the downloaded tiff or geojson into the layers panel
  6. Apply the downloaded .qml style file for labels and better visualization

Typical assets to download

  • data
  • style
  • thumbnail

How STAC Relates To The Public APIs

Use STAC when you want:

  • downloadable files
  • styles for QGIS
  • collection and item metadata
  • schema and field descriptions
  • browseable asset catalogs by geography or theme

Use Public APIs when you want:

  • precomputed data of some tehsils (active locations)

These are complementary:

  • STAC gives you asset-centric metadata and downloads
  • public APIs give you task-centric and app-centric payloads

Both connect back to the same computation and publication pipeline.

For People Adding Or Improving Metadata

The backend spec source to keep in mind is:

  • core-stack-backend/computing/STAC_specs

When adding or improving metadata, make sure the resulting items explain:

  • what the dataset is
  • which geography and time window it covers
  • which asset is the primary data asset
  • whether a style file exists