Awesome app. Handy not only for Freshers but also apparently me, a 4th year, as I didn't know where half those buildings were!
This tool is used for testing a device's accelerometer and magnetic field sensors. In addition to showing a basic graphical compass, it reveals the raw data of accelerometer and magnetic field. It also allows users to remap coordinate system, which is useful for developers to learn or verify coordinate system mapping.
The compass uses azimuth of legacy orientation sensor, which is shown in the first row of raw data. The orientation in the fourth row is calculated based on the rotation matrix after remapping coordinate system.