The Definitions and Comparative Analysis of the Relative Concepts of the Multi-city Spatial Complex

In view of the controversies over some concepts related to the multi-city spatial complex in present academic field,the paper now gives definitions to city groups,(large) metropolitan districts,(large) metropolitan circles,city-and-town concentrated areas,urban agglomeration and megalopolis as well as(large) metropolitan zones.It regards them as different forms of urbanization in its development phases and finds the inner horizontal ties and vertical ties between these relevant concepts of multi-city spatial complex.Finally the paper draws a comparative analysis over the relative concepts in horizontal and vertical ties.