Total gradient amplitude transformation

[leomiquelutti]

Description of the desired feature:

A nice transformation to add to harmonica is the total gradient amplitude (aka analytic signal), defined in Roest et al (1992) as $$|A(x, y)| = \sqrt{\left( \frac{\partial M}{\partial x} \right)^2 + \left( \frac{\partial M}{\partial y} \right)^2 + \left( \frac{\partial M}{\partial z} \right)^2}$$

Roest, W. & Verhoef, Joyce & Pilkington, Mark. (1992). Magnetic interpretation using 3-D analytic signal. GEOPHYSICS. 57. 116-125. 10.1190/1.1443174.

Are you willing to help implement and maintain this feature?

I will try to implement it but no promises about maintenance 😅