It seems that they want a smooth random vector field. Why don't they build that, which is easy to do? Why do they want, specifically, a field of angles? You c

It seems that they want a smooth random vector field. Why don't they build that, which is easy to do? Why do they want, specifically, a field of angles? You cannot average angles, and smooth noise, being computed by local averaging, is not going to work well for angles. But you can average vectors.