find angle of propagation in matlab

Hello, I have a matrces with values which when they are ploted the give a plot as attached.

red is high values green is low values.these red green stripes represent the direction of propagation of a field.

I need to find a way for matlab to recognise the angle alpha between the axes and the propagation direction of the field.

i have matrices values that created this plot.

Is there some way to find the angle between direction of propogation and one of the axes?

One idea is to use gradient ,but how to find an angle between gradient vector and axes?

Thanks.

Answer 1

[Matt J]

https://www.cuemath.com/geometry/angle-between-vectors/