mySpeedmeter (mySpeedo) shows you the speed at which youre currently travelling on your Device. Either as km/h, miles, knots or m/s. It also has a Companion App for your appleWatch, so that you can see these values directly on your wrist too.
It requires access to your location to be able to calculate the speed and the display does not go into sleep mode while using the app, so that you can see the values without having to tap on the screen all the time, to prevent to having it going dark. This might increase you battery consumption, so it might be useful to attach your device to a power cord while using the app for a prolonged time.
Activating the tracker mode will display the current Location as a readable String, this requires access to the Internet, so that the app can convert the current coordinates into an address.