Research On The Population Flow Network Of The Yangtze River Delta Urban Agglomeration Based On Micro-blog Check-in Data

The research on urban agglomerations has lasted for hundreds of years,from the formation and development of urban agglomerations to the spatial organization structure of urban agglomerations.In the past,the research on urban agglomerations mainly focused on the entity analysis of geographical space.With the development of society,the communication between cities and residents is no longer limited by geographical location,and urban agglomerations have the trend of integration.At present,most scholars at home and abroad begin to use the flow data to study the urban agglomerations.Most of them study the urban network structure through traffic flow elements such as railway flow and air flow;study the evolution of urban network pattern through enterprise flow;study the urban spatial organization structure through information flow.The traditional statistical data or questionnaire are still used in data acquisition.With the popularity of the Internet,the network not only affects people's daily life,but also affects the flow of population between cities.The data provided by the network platform has the characteristics of large amount,real-time and real,so it is more intuitive and scientific to use these data for analysis.The Yangtze River Delta urban agglomeration is a well-developed urban agglomeration which started earlier in China.China has made many policies to promote the integration process of the Yangtze River Delta urban agglomeration.This paper uses the user sign in data obtained from Sina Weibo platform to build the population flow network of the Yangtze River Delta urban agglomeration.Based on the analysis of the actual contact strength between the cities in the Yangtze River Delta,it can more truly reflect the characteristics of the network structure of the Yangtze River Delta Urban Agglomeration and its main influencing factors,which can provide corresponding suggestions for the future integrated development planning of the Yangtze River Delta urban agglomeration.The results show that:? the spatial distribution of check-in points is not only related to the level of urban development,but also affected by the location of urban functions and geographical location.The first tier cities have the most intensive check-in points;in addition to the first tier cities,functional cities such as transport hubs play an obvious role in gathering;there are characteristics that coastal cities are denser than inland cities,and urban agglomerations are denser outside than urban agglomerations.? From the perspective of urban nodes,the population flow network of the Yangtze River Delta Urban Agglomerations presents a pyramid level feature of "one core and three sub cores".Shanghai occupies the core position of the urban agglomerations with the highest centrality.Hangzhou,Nanjing and Suzhou are the "three sub cores",and the number of cities from the core level to the edge level gradually increases.?From the overall point of view of the network,the overall density of the population flow network of urban agglomeration exceeds the corresponding reference index,which shows that the overall relationship between cities is close.?From the perspective of network sub structure,except for"one core and three sub cores",other cities are affected by the provincial administrative divisions,showing the trend of clustering within the province,and there is a slight re stratification of"small groups" within the province.? Rich tourism resources,unique features,convenient transportation,high visibility of the city,economic development and infrastructure construction are the main factors to attract people to the core sub core cities.