Average height of a breaking wave in metres (m) . In surfers terms, the wave heights are measured by:

• Knee high - 1 ft (0.3 metres)
• Waist high - 3 ft (0.9 metres)
• Head high - 5 ft (1.5 metres)
• Over head - > over 6ft (Over 2 metres)

Beach Length

Length of beach in kilometres (0.1 = 100 metres, 0.5 = half kilometre, 1.0 = one kilometre, etc). If a beach length is less than 100 metres, we just call it a 'small' beach