As Figure 1.1 shows, the transition between land and ocean is often gradual, depending on local biophysical conditions. The issue here is not the nature of the actual transition, but what its implications are for defining a coastal area. Choosing the thresholds which define the landward and seaward limits of a coastal area depends to a large extent on why the
definition is needed. This ‘need-driven’ approach to coastal area definition is discussed further in the next section