Cotidal lines connect points on the rotary wave that experience high tide at the same time. Cotidal lines are not evenly spaced because tides are shallow water waves and their celerity depends upon water depth. Corange circles are lines connecting points which experience the same tidal range. The lines form irregular circles which are concentric about the node.
Tidal range increases outward from the node.
Amphidromic systems rotate clockwise in the southern hemisphere and counterclockwise in the northern hemisphere because of the difference in the direction of Coriolis deflection. Irregular coastlines distort the rotary motion. Actual tide expressed at any location is a composite of 65 different tidal components.