A GPS Speedometer is an application that transforms a device into a fully functional Speedometer, capable of reporting speed in kph or mph.
It works by using GPS signals using the devices in-built antennas, calculating the speed based upon distance & time the device has traveled.
These applications update in real time, and can also show your current direction as a compass would.
It will also display thee total distance traveled, has the ability to store the top speed undertaken, and like a gps tracker, will show your current location on a map.