Spatial Differentiation And Influence Mechanism Of Inter-provincial Immigration In The Yangtze River Delta

In the context of the slowing down of population migration across the country,how to improve the population attractiveness of this region is extremely important for economically developed regions such as the Yangtze River Delta.Based on migration "flow" data of the 2000 population census and the 2010 population census at the provincial level,this paper introduced the circos diagram of biology,and used R language to realize the spatial visualization of migration data,providing a new choice for the intuitive expression of "flow" data;GIS was used to reveal the spatial and temporal evolution characteristics of inter-provincial immigration in the Yangtze River Delta and the agglomeration trend and spatial heterogeneity;Based on the improved gravity model,OLS,SLM,SEM and GWR models,the influencing factors of inter-provincial immigration were quantitatively studied from two scales of province(city)and county(district).The main research contents and conclusions are as follows:(1)Intuitive expression of "flow" data based on circos diagram.Circos diagram was adopted to realize the intuitive expression of inter-provincial migration data.The results show that this method can present the characteristics of "flow" data more intuitively and clearly,and can still keep the map clean,orderly and beautiful under the premise of carrying more data,but it lacks spatial location information.(2)Statistical analysis of inter-provincial immigration in the Yangtze River Delta.Zhejiang is the preferred destination for immigration to the Yangtze River Delta,and Anhui province is the main source of migration.From the perspective of the total inter-provincial immigration,Shanghai "stands out",the migration intensity of Zhejiang is generally higher than that of Jiangsu,and the migration intensity of the 2010 population census is further strengthened.The inter-provincial migration within the Yangtze River Delta is very active,and Shanghai has an absolute advantage.The migration of Jiangsu into Shanghai is the main migration flow in the region,and the imbalance in Zhejiang is stronger than that in Jiangsu.(3)Spatial statistical study of inter-provincial immigration in the Yangtze River Delta.The spatial autocorrelation of immigration is not obvious,and that of immigration rate is very significant.From the perspective of geographic concentration index,the inter-provincial immigration population of the two censuses is less concentrated in spatial distribution,showing a decentralized distribution trend,but the trend is not obvious.The center of gravity of immigration tends to shift to south and to east.In the two periods,the spatial distribution of immigration is very unbalanced,and the distribution is developing in an unbalanced direction.(4)Research on the influence mechanism of inter-provincial immigration at the county(district)scale.By constructing multiple models to analyze the factors affecting immigration,and selecting the optimal GWR model,the regression relationship and spatial variability of inter-provincial immigration rate and impact factors were quantitatively studied.And the most sensitive factors of positive and negative were deeply analyzed.It was concluded that land urbanization rate and the number of health facility beds per thousand people are the main positive factors affecting immigration,and the biggest negative factor is mainly population density.(5)Research on the influence mechanism of inter-provincial immigration at the province(city)scale.The results of influence mechanism based on the improved gravity model showed that the positive and negative effects of the coefficient in 2000 and 2010 are basically the same,except the number of health facility beds per thousand people in the provinces of outmigration.In 2000,this index has a positive impact,and in 2010,it has a negative impact.The factors that play a "promoting" role in immigration are: population density in the provinces of immigration,urbanization rate in the provinces of immigration;The factors that have the function of "restraining" are population density in the provinces of outmigration,spatial distance and the proportion of GDP of tertiary industry in the provinces of outmigration.Based on the results of the two years,the influence intensity of explanatory variables is the proportion of the GDP of the tertiary industry in the provinces of outmigration,the population density in the provinces of immigration,the urbanization rate in the provinces of immigration,the number of beds in the provinces of outmigration,the population density in the provinces of outmigration,and spatial distance.