WITSML Trajectory Station Corrections Applied Calculated gravitational field strength correction. The correction applied to the X cross-axial component of the earths magnetic field. The correction applied to the Y cross-axial component of the earths magnetic field. Axial magnetic drillstring correction. Cross-axial magnetic correction. Cross-axial magnetic correction. Calculated sag correction to inclination. Calculated sag correction to azimuth. Magnetic declination used to correct a magnetic survey station. Grid Correction (Meridian convergence). The angle between True North and Grid North. Grid Correction is positive when True North is west of Grid North. The correction is added to the raw observation, thus yielding a reduced or corrected observation that can go into the subsequent calculations. Offset relative to bit.