The Map Selection icon allows you to select a map to display. The maps are divided into Local Maps and All Maps.

Local maps are the maps that are applicable to your current GPS location, whereas All Maps are the complete map catalogue.

The download state for the maps is also displayed:

Saved means the complete map including all areas it covers is saved on your device.
Sections Saved denotes that select parts of the map are saved on your device. An example will be the Mega charts which cover whole countries, or even the whole world. Sections of the maps can be downloaded by tapping on the map under Settings > Data Downloads.
Not Saved means no part of the map is saved locally on your device. You may still be able to view these maps if you are currently connected to data. The parts of the map you are viewing will be downloaded as you view them, but not saved to your device. If you wish to view a Not Saved map when not connected to data (e.g. in flight), download and save the map to your device.

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