BirdRing default uses Google Maps. However, this only works when there is an internet connection available. To use a map without internet connection, BirdRing can use offline map files that you have preloaded on your device.
You can activate the use of offline maps BirdRing menu: tap the three dots in the upper right corner and then choose Settings. Then you are guided to download a map of the country of your choice. You can also download multiple map files. Map files of some countries can take up quite some space on your phone or tablet. For the largest countries, you can choose to download one or more smaller regional map files instead.
The map files are based on OpenStreetMap data in MapsForge format.
Changes from August 2021:
Soon it is required that Android apps in the Google Play Store have implemented new security standards. In recent versions of Android, the use of files that have been stored on the device has been changed. The purpose is protecting your privacy: prevent apps to view all files on your device.
This means that BirdRing can’t use map files that have been downloaded with older BirdRing versions.
To use offline map files, you must go to Settings in BirdRing and then create or choose a folder (directory) for map files. That folder can for security reasons not be the Downloads folder from Android version 10, but you can create a subfolder like Downloads/BirdRing or Downloads/maps. You can also create a folder on a different location or choose an existing folder. If you like, you can move existing .map files to this new folder. Download new map files from BirdRing is also possible of course. Your map files will be completely up-to-date.
Hint: map files can be quite large. Therefore, if you also have other apps that use the same OSM MapsForge map files, choose the same folder for map files in all those apps.