Wave

Wave is an app that can tell you exactly where your friends and family members are in real time, using an accurate geolocation system. Of course, you'll only be able to know the location of another person if the other user accepts it first.

To start using Wave, you first have to create an account using a valid telephone number. Once you've created an account, you can start "waving" at your contacts. When you send a "wave" you'll be able to choose how long you'd like to be able to see the other person's location. The other person needs to accept in order for you to see where they are.

The main reason for using Wave is pretty obvious: when a friend, family member or acquaintance is going somewhere, you can "wave" at them for their own safety. This way, if you see that the other user has taken an unexpected turn, has stopped or isn't responding to your messages, you'll know that something is wrong.

Wave is a very useful app, that lets you tell your friends where you are and know where they are.