Analyzing The Spatial Characteristics Of Urban Streets And Minning The Relationships With People Activities

Street space is the basic unit of cities and the important multifunctional element carrier.However,the current studies focus on a dimension measure of street space and ignore the relationships between street space elements.Therefore,this paper focuses on the characteristics,external representation and the relationships between them.From the three macro,normal and micro angles,big data and artificial intelligence technology are used to realize the topological analysis of the street spatial layout in Beijing sub-central,the extraction of scene components,the identification of different functional types,and then analyze street spatial morphology,quality,function and other characteristics.On this basis,the spatial and temporal laws of street activities are mined through mobile phone data,so as to explore the relationships between street spatial form,quality,functional difference and population vitality,and provide reference for urban street spatial planning and governance.The research results are summarized as follows:(1)Global accessibility presents the gradually decreasing circle structure from Beijing subcenter to the outside.There are certain number of old blocks in Beijing sub-center,but the street connectivity is good.The streets such as Xinhua,Beiyuan and Yuqiao are the not only the global center but also the local center of Beijing sub-center,which constitute the core area of the sub-center to some extent.(2)The street facilities level is generally low in sub-center.The facilities level and walkability in Liyuan,Yongshun Town are higher than other areas.However,the comfortableness of the space shows the characteristics of high value in the edge of the sub-center and low value in the core.Street intersections are safer,better traffic facilities and more walkability than the street midpoints.(3)The sub-center core area is obviously dominated by business,life and mixed function,with mixed functions.Sub-center periphery is dominant by traffic function.The centers of street life,business,comprehensive function are obviously distributed along the both sides of subway and bus line.(4)Young people aged 25-44 are the group with the highest concentration in street space.Population vitality gather at a small number of streets.About 20 percent of the street grids attract80 percent of the population.People of all ages have high concentration in Beiyuan South Road,Baliqiao South Street,Jiukeshu,Tonghu Street and Luyuan South Street.(5)On weekdays,population vitality in street space is mainly affected by commuting,presenting the "tidal variation".The peak of population concentration appears at 8 AM and 6 PM,and inflow and outflow population dominate alternately,showing the rule of "early departure and late entry ".To a certain extent,it shows that the street space has a strong "intermediary" role of position conversion.On weekends,the population of street space is active from 9 Am to 18 PM.(6)Building street spatial vitality from population density,inflow and outflow population and parked population.Street vitality has positive correlation with the accessibility of street network,function commercialization.The correlation between street quality and population vitality is relatively low.In addition,there is a correlation between the high spatial comfortableness and the characteristics of less commercial facilities.Should street space be dominated by efficient? Quality first or Functional connotation orientation? Through research and analysis,this paper holds that street form efficiency is the foundation,functional use is the support,environmental quality factor has the effect of beautifying streets,and street vitality is the result driven by multiple factors.The improvement of street vitality not only needs the optimization of street form structure and environmental quality,but also needs the adjustment of social and economic structure including street function.Street space is heterogeneous,and the people behavior and activity mechanism in street space is complex.Future research on street space should focus on the application of artificial intelligence and big data in spatial planning,and conduct multi-dimensional and fine-grained research from the perspectives of time,space and people.