A very reliable compass combined with a spirit level.
Even if you hold your device in an upright position in front of you, the exact cardinal point will be displayed.
The rotation in horizontal position can be measured with the compass.
The precision of the compass depends on your sensor. Magnets and electric fields have a magnetic field and thus have an influence on the compass.
Many great features:
* Set layout colors the way you like it
* Choose between portrait and landscape mode (optimized for tablets)
* Move the app to your sd-card
* Acoustic and visual feedback when the angles are equal to 0°
* Values can be displayed with decimal places
* Easy calibration (i.e. for levelling out the bulge of your camera)
* Adjust the sensibility of the measurement
* X and Y values can be swapped
To remove the ads you can buy the pro version 'Compass & Spirit Level Pro' in the app store. Additional you will get further features like displaying the strength of the magnetic field or setting the visual and acoustic indicator with a tolerance.
Some feedback would make me happy :) Please write an email to report any problems.