Research On Spatial Vitality Evaluation And Influence Mechanism Of Urban Blocks

As rapid urbanization has entered a new stage,cities have changed from incremental development to stock development,and remarkable results have undoubtedly been achieved.However,the extensive urban development left by the block size is different and too large,road traffic congestion and chaotic regulation,lack of public space and service capacity,chaotic living environment and other urban problems together lead to the damage of urban space quality,block vitality breakdown and other problems.It is an important topic to guide the sustainable development of the city how to serve the people,solve the current problems of the city with the local people,improve the quality of space use and rebuild the vitality of the city.At the same time,with the change of research methods,technologies and scientific research data,it has become a new idea of block scale research to rationally study urban problems,enhance the vitality of blocks and formulate strategies for vitality improvement by using emerging technologies and "big data" based on traditional research.In this paper,the FD-CR model is used to identify the function of the third ring road in Chengdu by using multi-source data such as Baidu Huiyan thermal map,Amap POI data,OSM third ring road data,vector data of Autonavi building,bus and rail transit data,and Homelink housing price data.Vitality is divided into external representation and internal components to establish an evaluation system.The external representation selects indicators from time,spatial aggregation and dynamics.On this basis,the vitality intensity model,vitality hot and cold aggregation,vitality stability model,whole-day and moment-to-moment vitality fluctuation characteristics,density stability cross classification were constructed to analyze the temporal and spatial characteristics of vitality.The attractiveness,diversity,compactness and accessibility of blocks are selected as indicators of vitality components.The influence mechanism and spatial heterogeneity of vitality were analyzed by geographical detector and geographical weighted regression,and finally the vitality promotion strategy was proposed.The main research results of this paper are as follows:(1)The classification of blocks is mainly residential blocks,supplemented by public management,commercial and green space blocks.A total of 1117 Chengdu Third Ring Blocks,298 mixed-function blocks and 817 single-function districts were obtained.(2)According to the vitality characteristics of the neighborhood,it is found that the low-vitality blocks are mainly residential blocks,public management blocks,and green space blocks;High-vitality neighborhoods are mainly commercial and partially residential blocks,and the proportion of commercial blocks has gradually increased from low vitality to high vitality.(3)The density of neighborhood vitality is similar,and the overall vitality of rest days is greater than that of rest days.The high-vitality neighborhoods are mainly commercial blocks,public management blocks and nearby residential blocks,which are distributed radially along the subway line.Low-vitality neighborhoods are mainly distributed outside the second ring road,and the spatial distribution is relatively scattered.The vitality fluctuation characteristics are similar,and the vitality value of rest days is formed on regional working days,and the lowest vitality value is formed at 5 o’clock and the highest vitality value is formed at 18 o’clock.(4)The low-low type is mainly residential,public management,and commercial blocks,mainly distributed outside the second ring road,and the vitality of this area is low;The lowhigh type is mainly residential,public management,commercial,and green space blocks,mainly distributed in the second ring area,with low vitality;High-low neighborhoods are mainly commercial and residential,mainly distributed in the second ring road,with high vitality and small variation,and strong vitality sustainability;High-low blocks are mainly distributed within the second ring road of the street,and the vitality of the block is strong and dissipates quickly;High-height neighborhoods are mainly residential and green space blocks.(5)The attractiveness of the block is the main indicator of the spatial differentiation of the vitality of the block,among which the density of commercial services and the density of public management have the greatest explanatory power.Excluding insignificant factors,the remaining 31 geodetectors showed nonlinear enhancement and two-factor enhancement.After the dominant factor of stepwise regression screening,geographically weighted regression was used to find that commercial facilities,functional mixture,public management density,and bus station density were all positively correlated.The spatial differentiation of floor area ratio,functional density and metro station point density was obvious,and there was a negative correlation in some areas.The remaining factors are negatively correlated with regions.The dominant factors of neighborhood vitality were all spatially heterogeneous,and the spatial distribution of the coefficients of each factor was significantly different.