# Data sources

No single source has correct cities, names, and borders for all countries.

## How Onde builds the dataset

- For each place, the build takes the most reliable facts from the sources.
- Onde adds what the sources do not have, such as common names, local names, and districts.
- Onde corrects errors by hand. Each correction that changes a fact cites its source.
- Each release must pass quality gates before it goes live. The gates check search, autocomplete, reverse lookup, a list of named cases, and the response time.
- A release keeps the ID of each city from the previous release.

## Open data

Some of the sources are open data. Onde changes and extends the data of these sources:

- [GeoNames](https://www.geonames.org), under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/).
- [Wikidata](https://www.wikidata.org), under [CC0 1.0](https://creativecommons.org/publicdomain/zero/1.0/).
- [Natural Earth](https://www.naturalearthdata.com), in the public domain.