title: Use of Scalar component in Rotation-Vector-Sensor?
body: <p>What is the use of the Scalar component of the Rotation-Vector-Sensor in Android? </p>
  
  <p>The documentation states it's optional and the samples don't use it. Does optional mean it's not supported by every device that supports the sensor?</p>
  
  <p>I'm used to quaternion style rotation notations where the first 3 values define the vector and the fourth defines the rotation around that vector. But android seems to use a different approach.</p>