How should I know, that child has left the selected zone?

You can define one or several zones, in which the child is used to be present/ should be present. For example, you can mark the zones such as “school”, “grandparent’s house” or “the pool”. When you mark an area (in the radius of minimum 100m and maximum 2500m), and set it as a e.g. “school zone”, you will receive a notification on your mobile device immediately when the child leaves the selected zone.