Main principle of metropolitan area's economic development and its enlightenment to construct Lanzhou metropolitan area

Metropolitan area is the outcome of economy development to a certain phase.Economy developmental is the important content of metropolitan area construction and improvement.The paper introduces corresponding theories of economy development,i.e.distance-decay law,the principle of gravity,central place theory,theory of region-production syntheses,the principle of absolute and comparative advantage,and network structure theory,which are positive and constructive to construct the metropolitan area.Nowadays special distance is not a main factor of limiting economy development,but spatial economy relation is still in accord with distance-decay law and the principle of gravity,so proximate cities/towns possess closer economy intercourses which is the essential condition to come into being metropolitan area.Development forms of metropolitan areas are various,which may include single centre mode,multi centre mode,and network mode and so on.Taking Lanzhou Metropolitan Area as an example,the paper briefly explains application of these principles on the course of actual construction.Combining distance-decay law and the principle of gravity defining,the scope of Lanzhou Metropolitan Area has been made;According to theory of region-production syntheses and the principle of absolute advantage and comparative advantage,Lanzhou Metropolitan Area is divided into different functional regions of economic development;Based on network structure theory,the paper have conceived Lanzhou Metropolitan Area's network economy model.In general,it is the prominent and innovative points in the paper that fundamental principles and theories of regional economy and economic geography are applied in the course of constructing metropolitan area.