Quantifying Urban Vitality And Its Growth Strategy Using Spatio-temporal Big Data

The rapid and large-scale urban construction presents an urgent challenge for developing a predictive,quantitative theory of"the death and life of cities".Jane Jacobs had a deep understanding of the complexity and the development of the city,providing a basic framework for assessing the vitality of the city.However,for a long time in the past,those theory have not been empirically tested all together mainly because it is hard to collect data about"urban vitality"and"urban diversity"in fine spatiotemporal granularity.In recent years,with the rapid development of information and communication technology(ICT),the value of various spatio-temporal data has been widely recognized,and those rich informative spatio-temporal data have been increasingly used in urban vitality research.Unfortunately,existing empirical research mainly measured the relationship between urban built environment and urban vitality,while time distribution and spatial interaction were ignored.In this paper,we use multi-source spatiotemporal data to measure the spatial and temporal diversity of cities by using the generalized entropy function,supplement the measurement system of urban diversity from the perspective of time and space synthesis,measure urban diversity more comprehensively,and identify the significant influencing factors that determine urban vitality.Taking Wuhan as an example,the urban vitality measurement method was practiced.It is found that 28 indicators such as attribute,time and space diversity are positively correlated with urban vitality;among them,the most relevant factors are attribute richness,attribute entropy index,attribute Simpson's index,time richness,time Simpson's index,and spatial entropy index.At the same time,the study found that attribute richness index,spatial entropy index,Simpson's index of building floors and POI density are the most significant factors.In terms of mechanism,the growth of urban vitality depends on the growth of the influencing factors of urban vitality.In order to promote the growth of urban vitality,the main method of existing research is to study the creation of urban vitality with specific cases,and lack a quantitative universal strategy.This paper finds that the density and richness of POI is one of the significant factors affecting urban vitality.Then,using the method of co-occurrence probability,a universal strategy of urban vitality growth based on POI space is proposed to show the composition and function of community function.Advantages,simulations predict the possible growth direction of community functions.In the practical study of the urban vitality growth strategy,it is found that the correlation between the more common POIs is higher than that of the more unique and rare POIs;the research results show that the analysis of the functional patterns of the POI space can be well reveal the differences between regions with different socioeconomic backgrounds;the speed and final outcome of the growth of POI categories in different communities depends on the distribution of their initial POI categories.