pydggsapi

pydggsapi is an OGC API – DGGS server implementation built with FastAPI, with IGEO7 as a natively supported Discrete Global Grid Reference System.

• Repository: https://github.com/allixender/pydggsapi
• Authors: Alexander Kmoch, Wai Tik Chan (University of Tartu)
• License: AGPL-3.0
• Paper: Kmoch, A., Chan, W.T. (2025). pydggsapi. FOSS4G 2025.

What It Does

pydggsapi implements the OGC API – DGGS candidate standard, exposing DGGS-indexed data over standardised REST endpoints. Any OGC-compliant client can query the server for cell data without knowing the underlying grid system.

Supported DGGS reference systems:

• IGEO7 (ISEA7H Z7)
• H3
• HEALPix
• rHEALPix

Supported data backends:

• Clickhouse — columnar analytics for large vector datasets
• Zarr — cloud-native array data (via xdggs)
• Parquet — file-based tabular data

Key Endpoints

Endpoint	Description
GET /dggs	List available DGGS reference systems
GET /dggs/{dggs_id}	Describe a specific DGGS
GET /dggs/{dggs_id}/zones	List zones (cells) at a resolution
GET /dggs/{dggs_id}/zones/{zone_id}	Get data for a specific cell
GET /collections	List data collections
GET /collections/{coll}/dggs/{dggs_id}/zones/{zone_id}	Get collection data for a cell

Quick Start

pip install pydggsapi
uvicorn pydggsapi.main:app --reload

The server starts at http://localhost:8000. The interactive API docs are at http://localhost:8000/docs.

Configuration

Configure data sources and DGGS settings via environment variables or a config file. Example for IGEO7 + Zarr backend:

dggs:
  - id: IGEO7
    type: ISEA7H_Z7
    resolutions: [5, 7, 9, 11]

collections:
  - id: sentinel2_ndvi
    backend: zarr
    path: s3://my-bucket/sentinel2_ndvi.zarr
    dggs: IGEO7
    resolution: 9

See Also

• OGC API DGGS — the underlying standard
• Xarray-XDGGS — the Zarr backend integration