Tidal range standard : Sort the local daily tidal range in descending order, take the first(latter) 1/3 of the value as the "Standard of spring(neap) tide".
Spring : Daily tidal range ≥ "Standard of spring tide"
Moderate : "Standard of neap tide" ≤ Daily tidal range < "Standard of spring tide"
Neap : Daily tidal range < "Standard of neap tide"
