In addition, ACD is an economic geographical concept and it is not necessarily lies in the physical apex of the delta, i.e. the physical and the economic apex of delta are not superposed. 5.

• 另外，三角洲顶点城市是一个经济地理范畴内的概念，该城市不一定正好处于三角洲的自然顶点区位，即三角洲自然顶点与经济顶点不具备完全吻合性。