Oh, if you have a compass, yes, that would be good. A compass is based on an absolute (the magnetic field of the earth), so the values won't drift with inaccuracies. However, a compass' readings are very negatively affected by it's surroundings, so the immediate accuracy could be off significantly.
Ideally you would use both the compass and the encoders, and combine the values using a filter. It would be very complicated, and certainly not something I would recommend for a beginner (or even someone that is intermediate).
I'm all for gun control... that's why I use both hands when shooting