Understanding Tie Point Geometry


#1

Hello,

I do not understand the viewing azimuth angles (OAA) in the Sentinel 3 OLCI Tie Point Grid bands.

On the right side of my image, the OAA values suddenly flip to negative, as shown in the profile plot below. This limit seems to correspond to one of the “cameras” I believe. Is this an issue or am I not understanding the data correctly?

Cheers,

Max


#2

Hi Max,

The flip occurs at nadir. OLCI is tilted a bit, that’s why nadir is not in the centre.
The the sum of the left and right side of the nadir is 180°. Not considering the sign.
So I guess it is correct, but honestly, I always mix those angles up.
You can open directly the tie_geometries.nc file in SNAP or something else. There you see the not interpolated angles