Evaluation Of Urban Vitality And Analysis Of Spatial Distribution Differences In Metropolitan Areas Based On Multi-source Data

In the process of rapid urbanization,population growth and urban space expansion in metropolitan areas have brought tremendous pressure to sustainable urban development,supply and demand have created spatial dislocations.The interaction between the physically built space and the space of human social activities,especially at the local scale,has not been deeply research.Urban vitality is an intuitive reflection of the quality of life within the city and the efficiency of urban resource utilization.Accurate evaluation of urban vitality in metropolitan areas has important guiding significance for the efficient use of urban resources and the optimization of regional vitality.In this paper,four typical metropolitan areas of Beijing,Shanghai,Guangzhou and Wuhan are taken as research objects.Based on 500m*500m grid spatial units,impervious surface data,urban road network data,points of interest(POI)and Tencent location big data are obtained,in order to construct a urban vitality evaluation system to evaluate the vitality of metropolitan areas from a new perspective.Based on the inconsistency of the spatial distribution of physical vitality and social vitality,the concept of Matching Degree Index(MDI)is proposed,the MDI is constructed and the matching degree is divided into four types.Analyze the spatial auto-correlation of the matching index based on Moran’s I index;quantitative identification of urban functional areas based on POI,measurement of land use mix based on entropy index to explain the influence mechanism of the matching index,and put forward suggestions for optimization of urban vitality improvement.The main research conclusions are as follows:(1)The physical vitality and social vitality of the metropolitan area are inconsistent in spatial distribution and quantity distribution.In terms of spatial distribution,there is an agglomeration difference between them: the high value of physical vitality is continuously distributed in the city and the scale of agglomeration is large;the high value of social vitality is mainly concentrated in the core area of thecity and the agglomeration scale is small.In terms of quantity distribution,the physical vitality value is much higher than the social vitality value.The average physical vitality value in the study area is nearly 12 times the social vitality value;the distribution of social vitality values is more concentrated.(2)The MDI shows a spatial distribution pattern with high concentration in the core area and scattered sporadic periphery,and has a strong spatial auto-correlation.The degree of matching gradually decreases outward from the core area,and there is a spatial mismatch between the physical vitality and social vitality in the periphery of the core area.The high-matching degree clusters are distributed in the core area,and the middle-matching degree surrounds the high-matching degree periphery;the low-matching and non-matching are scattered and scattered.(3)The MDI of mixed functional areas is higher than that of single functional areas,and the improvement of land-use mixing degree helps to improve the matching index.To single functional area,the matching degree of commercial and industrial land is high,and that of residential land is low;the matching degree of mixed functional area is related to its dominant function type and mixing ratio.Commercial function has a positive impact on the matching degree,residential function And green land have a negative impact on the matching degree;the improvement of the land-use mixing degree helps to improve the matching degree.(4)There are differences in the matching degree of urban vitality in the main urban areas of metropolitan areas.The main city of Guangzhou has the highest degree of matching and less spatial heterogeneity,which is related to the agglomeration and distribution of urban factors,higher land-use mix and active commerce;Followed by Wuhan and Shanghai,the MDI of Wuhan’s main urban area is a multi-center spatial distribution pattern;the matching degree of Puxi in Shanghai’s main city is higher than that of Pudong;the matching degree of Beijing’s main city is the lowest and the spatial heterogeneity is greater.The matching degree in the east of the core area is higher than that in the west,and the proportion of mixed functional areas in the main city is small.In the next step of urban planning,we should guide the construction of urban multi-center structures;optimize urban functions,evacuate core area functionsand focus on the planning and layout of mixed function areas.