QGC shows a clockwise positive angle (0 → 360º).
MavLink sends the angle between -pi and +pi, where the positive angle is the clockwise direction and zero is north.
+------------+-----------------------+----------------+----------------+------------------+--------------------+---------------------+-------------------+--+---------------------+--------------------+
| timestamp | ATTITUDE.time_boot_ms | ATTITUDE.roll | ATTITUDE.pitch | **ATTITUDE.yaw** | ATTITUDE.rollspeed | ATTITUDE.pitchspeed | ATTITUDE.yawspeed | | yaw (grad -180|180) | yaw (grad 0 | 360) |
+------------+-----------------------+----------------+----------------+------------------+--------------------+---------------------+-------------------+--+---------------------+--------------------+
| 1517566176 | 292507 | -0.03405671939 | 0.09500097483 | **-3.108595848** | 0.002565450035 | -0.003794062883 | -0.02150129899 | | -178.1146754 | 181.8853246 |
+------------+-----------------------+----------------+----------------+------------------+--------------------+---------------------+-------------------+--+---------------------+--------------------+
To generate a csv from tlog, you can check Mavgen.py to translate, but how? - #2 by patrickelectric