The core areas include the following categories: [1]
① Domestic metropolitan areas; [1]
② Regional central city; [1]
③ The center of the subregion; [1]
④ Local service center. [1]
The core region and marginal region will change with the development of economy. Friedman once made an example analysis of the core periphery model of the United States. He believed that in the 19th century and early 20th century, with the concentration of capital and labor from Europe in the northeast of the United States, the northeast became the center of American manufacturing industry, which made the regional economy develop rapidly and became the core region. After the region became the core region, due to the effect of agglomeration economy and economies of scale, the northeast coastal area developed into a huge urbanization region. At that time, California was still a resource-based marginal area. Later, with the discovery of gold mines and the influx of immigrants, urbanization developed rapidly, and it became a major sub core area in the United States. At that time, most of the southern regions were relatively backward in economy, with low urbanization level and low income, and they belonged to obvious marginal regions. Later, with the outward expansion of the manufacturing industry in the Northeast, the economic focus of the United States shifted to the south and west, and the wealth shifted to the south and west. The national industrial layout was adjusted, which changed regional relations. Although the contrast between the core area and the edge area still exists, the intensity has been greatly weakened. With the formation of the huge urban belt along the western Pacific coast and the formation of the urban belt along the eastern Pacific coast, they stand side by side with the five major urban belts in Hunan, expanding the scope of the core region and sub core region, greatly narrowing the marginal region, and greatly improving the unbalanced development between regions. [1]
