Among the various functions of the Altimeter GPS app is also the distance calculation. It is an exclusive function based on a proprietary algorithm and developed ad hoc. It allows you to calculate the distance from where you are in the air.
Simply move the wheel to the right with the meter indicator, and frame the destination point with the camera. The red line indicates the length of the selected distance to the side, while at the top it is possible to display the estimated altitude in meters of the framed point.
Attention, the arrival point of the red line must coincide with the point framed in the camera to have a reliable measurement.
The distance calculation can be accessed by pressing the blue button in the second slide of the main menu.