The view zenith angle shows inconsistencies at nadir direction - why?

[rese_support]

The produced zenith scan angle map is the effective scan angle per image pixel. By convention, it is negative for left looking and positive for right looking pixels. If now a pitch offset is included in the data, the scan angle will never go through zero, since even in 'nadir' the sensor looks a little forward in flight direction (ie. at the angle of pitch boresight). However, there is still this change of sign as soon as the direction changes from 'left' to 'right' in relation to the flight direction. If you don't need the information about the view sense, you could just take the absolute value of the zenith angle and the apparent inconsistency will no longer disturb (you still have the viewing direction from the view azimuth).