This is an open source project developed by Antoine Meler. The source code is available on GitHub under the GPLv3 license; the app is also available on Google Play.
This app does not collect any user information. You can let the app/web site know your location to zoom in but this information is used solely locally and is not sent to the server.
If you have any question regarding how the app protectes your privacy, please send me an email.
Cheers, Antoine Meler, [email protected]