As one of the geographic units in the progress of a country's integrated strength, metropolitan area is the powerful engine in the development of economy. Essentially, metropolitan area consists of a core city which has strong economic potential and radiating capacity as well as several neighboring cities. Due to the "distance decrement", it represents a relatively obvious circle-layer mode as moving outward. For example, the single-center metropolitan area is represented by "nucleus area (layer) clear understanding of the spatial scope of metropolitan area is the foundation of research. Accor...
