in the code imgradient3 and also in imgradient; Gazimuth = atan2(-Gy,Gx)*180/pi. My question is why this -Gy is used?

My question has two parts. 1. When imgradient3 calculates Gazimuth, it uses the following equation Gazimuth = atan2(-Gy,Gx)*180/pi. Why -Gy is used instead of Gy in the equation? 2. How to get back of Gx, Gy, Gz values from Gmag, Gazimuth and Gelevation? When I was trying to get Gx, Gy, Gz values using simple geometry, I am getting everything right except an opposite sign for Gy.

Thanks in advance.

Answer 1

[Stefan Philippo Pszczolkowski Parraguez]

Use imgradientxyz instead if you are interested in Gx, Gy and Gz