# Third-party data & attributions

TREK bundles and uses third-party data that requires attribution.

## geoBoundaries — country & sub-national boundaries

The Atlas map's administrative boundaries (admin-0 countries and admin-1
provinces/counties), shipped at `server/assets/atlas/admin0.geojson.gz` and
`server/assets/atlas/admin1.geojson.gz` and generated by
`server/scripts/build-atlas-geo.mjs`, are derived from **geoBoundaries**.

> Runfola, D. et al. (2020) geoBoundaries: A global database of political
> administrative boundaries. PLoS ONE 15(4): e0231866.
> https://doi.org/10.1371/journal.pone.0231866

geoBoundaries is licensed under **CC BY 4.0**
(https://creativecommons.org/licenses/by/4.0/). Source: https://www.geoboundaries.org/

The bundled files are simplified (coordinate-quantized) and re-tagged with the
property names TREK consumes. Country borders (`admin0`) derive from the geoBoundaries
CGAZ composite; sub-national regions (`admin1`) derive from the per-country open
(gbOpen) release.

## OpenStreetMap — geocoding, place details & descriptions

Atlas reverse-geocodes places via the **Nominatim** service, and place search,
details and descriptions come from Nominatim and **Overpass**. Data is
© OpenStreetMap contributors, licensed under the Open Database License (ODbL).
https://www.openstreetmap.org/copyright

## Wikimedia Commons & Wikipedia — place pictures & descriptions

Pictures offered for a place come from **Wikimedia Commons** (geosearch by
coordinate) and are cached locally rather than hotlinked. Descriptions can come
from **Wikipedia**, resolved from the place's OpenStreetMap `wikipedia` tag.

Commons files carry their own licence, most often **CC BY** or **CC BY-SA**. TREK
shows the author, the licence and a link to the file description page next to
every picture while it is being chosen, and keeps the author and licence with the
cached file so the credit stays visible afterwards. Wikipedia article text is
**CC BY-SA 4.0**. https://commons.wikimedia.org/wiki/Commons:Licensing

## Google Places — optional place data

When an administrator configures a Google Maps API key, place search, details,
pictures and editorial summaries can also come from the **Google Places API**,
subject to Google's terms. Photos carry the author attribution Google supplies
and no reusable licence; TREK displays that attribution and claims nothing
further. This path is off unless a key is configured, and each part of it has its
own switch in the admin panel. https://cloud.google.com/maps-platform/terms

## OurAirports — airport reference data

`server/assets/airports.json` is built from **OurAirports**
(https://ourairports.com/data/), released into the public domain.