# Helsinki data: licence

The Helsinki city data in this folder is generated by `tools/helsinki/build-helsinki.mjs` from OpenStreetMap and
National Land Survey of Finland (Maanmittauslaitos, MML) open data:

| File | Contents | Sources |
|------|----------|---------|
| `geodata.js` | roads and road graph, blocks, parks, land and water, tram and rail tracks, platforms, metro entrances, place names | OpenStreetMap; land/sea from MML Korkeusmalli 2 m |
| `building-geodata.js`, `building-geodata.bin.gz` | building footprints, roof heights, construction decades | OpenStreetMap; roof heights from MML 3D-rakennukset LOD2 |
| `tree-geodata.js`, `tree-geodata.bin.gz` | tree locations | OpenStreetMap |
| `terrain-geodata.bin.gz` | ground height grid | MML Korkeusmalli 2 m; road bridge decks from OpenStreetMap |

## Licence

These files together are a derivative database of OpenStreetMap and are made available under the
**Open Database License (ODbL) 1.0**: <https://opendatacommons.org/licenses/odbl/1-0/>.
Any rights in the individual contents of the database are licensed under the Database Contents License:
<https://opendatacommons.org/licenses/dbcl/1-0/>.

The MML data in them is used under **Creative Commons Attribution 4.0** (CC BY 4.0):
<https://creativecommons.org/licenses/by/4.0/>, see <https://www.maanmittauslaitos.fi/en/opendata-licence-cc40>.

## Attribution

- © OpenStreetMap contributors, <https://www.openstreetmap.org/copyright>
- Contains data from the National Land Survey of Finland (Maanmittauslaitos), Korkeusmalli 2 m and
  3D-rakennukset, 2026, CC BY 4.0

The rest of the program (the engine and the other `js/` modules) is under the MIT licence in `LICENSE`.
The live tram, train and ferry positions are fetched at run time from HSL and Fintraffic (digitraffic.fi),
CC BY 4.0, and are not part of this database.