Take a GeoJSON as an input, take all H3 hexagons within and output GeoJSON hexagons with their id

geojson_to_h3_hexagons.py

from h3 import h3

geoJson = {'type': 'Polygon', 
    'coordinates': [[[37.813318999983238, -122.4089866999972145], 
    [ 37.7866302000007224, -122.3805436999997056 ], 
    [37.7198061999978478, -122.3544736999993603], 
    [ 37.7076131999975672, -122.5123436999983966 ], 
    [37.7835871999971715, -122.5247187000021967], 
    [37.8151571999998453, -122.4798767000009008]]] }

hexagons = h3.polyfill(geoJson, 8)

print(h3.h3_to_geo_boundary(list(hexagons)[0], geo_json=True))


geojson_out = {
  "type": "FeatureCollection",
  "features": []
}

for i in hexagons:
    geojson_out["features"].append({
      "type": "Feature",
      "properties": {
          "identifier": i
      },
      "geometry": {
        "type": "Polygon",
        "coordinates": [
            h3.h3_to_geo_boundary(i, geo_json=True)
        ]
      }
    })

with open("/tmp/output.geojson", "w") as outfile:
    json.dump(geojson_out, outfile)