Using long pressing the volume controlling buttons to start functions in Locus
At the moment, it is possible to assign a volume controlling hardware buttons to zoom the map.
I'm not sure whether the Android API does this, but it would be useful for some types of weather conditions (for example - in winter or under heavy rain, when it's hard to use soft buttons) make it possible to assign some functions to long (>1 sec) presssing these buttons.
For example, one button can be configured to create a new POI, another - to activate the screen magnifier. And some functions can be launched even without unlocking and without getting the phone out of pocket (creating a POI, recording a track, etc.)