The Applied Research of the Spatial Defining Methodology of Metropolitan Area - Taking the Pan-Guangzhou Metropolitan Area as an Example

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) - close-related layer - periphery layer" from the inside out. A clear understanding of the spatial scope of metropolitan area is the foundation of research. According to Gao and Luo, there are some basic principles when dividing the regional economy of China, such as centering on the core city, depending on the urban system, linking by the quality of transportation, and considering the consistency of administrative division and economic division. However, the development of Chinese metropolitan area has faced several bottlenecks: administrative barriers, market order, the allocation of interests and so on. It would be difficult to have a breakthrough in the development of metropolitan area unless those key problems were solved.