Regional Differences and Spatial Pattern since Reform and Opening Up in Ningxia——Based on the Evolutionary Character and the Coupling Relationship of Gravity Center of Population, Economic and Grain
利用重心模型计算宁夏各县人口、GDP和粮食产量的重心，分析其动态演化、驱动因素及耦合关系，发现经济重心偏北且移动小，人口重心快速北移，粮食重心最不稳定，经济与粮食耦合度低。
Using the concept of gravity center and correlation formula, applying various counties in population, GDP and crops yield data to calculate the gravity center of population, economic and grain, study their dynamic evolution, driving factor and coupling relationship. Results show: ① Economic gravity center in north is obvious and its movements are small; ② Population gravity center quickly moved from south geometric center to the north, this trend will continue to persist and the movements are larger;③Grain gravity center is mainly located in the north side of the gravity centre, the movements are the largest and the most unstable, and no obvious regularity;④The space coupling of gravity center of economic and grain is not high, gravity center of population and grain have the space coupling, the space coupling is most obvious in economic and population.