Notes: Good ground swells (long period swells) have strong colour away from the middle, chop is energy towards the middle (short period).
A stripy curve of the same period energy is preferable to a blotch or a range of periods.
Spring surf31 August 2015 - note the choppiness to the surface, especially out-the-back.
This is the green shading to the top of the graph.
Autumn surf23 March 2016 - Again there is choppiness to the surface.
Note the difference in the green shading to the Spring graphic above and the different strengths of the various periods.