A Study On Urban Vitality Of Chengdu City Based On Multi-source Spatiotemporal Data

In the context of China's extensive urban development model,urban planners are forced to change their original planning perspective due to urban problems such as population loss,traffic congestion and job-housing imbalance.The concept of urban vitality is put forward to measure the rationality of urban spatial planning.Creating balanced urban vitality and improving the quality of urban space are of great significance for sustainable and high-quality urban development.Based on the spatiotemporal data of tencent travel,this paper analyzes the spatiotemporal changes of urban vitality and its influencing factors from the perspective of the dynamic characteristics of residents' activities,so as to further enrich the research on urban vitality and provide a scientific basis for the planning of urban spatial structure and the improvement of urban vitality.This paper takes the downtown area of Chengdu as the study area and combines multiple open source data such as Tencent travel data,POI data and OSM road network data.Firstly,it analyzes the spatio-temporal evolution characteristics of urban vitality in the downtown area of Chengdu from the two time dimensions of different characteristic days(working days and rest days)throughout the day and different periods of the day.Secondly,the FD-CR model is used to identify the functional areas in the downtown area of Chengdu,and on this basis,the dynamic evolution and differences of various typical functional Spaces are analyzed.Finally,the influence index system is constructed,and the correlation between urban built environmental factors and the spatial and temporal distribution of urban vitality is studied and analyzed by using geographic detector.The results show that:(1)The spatial distribution of urban vitality varies greatly between working days and rest days.The spatial distribution of working days is characterized by circle-layer weakening and double-center structure,while the spatial distribution of rest days is characterized by circle-layer weakening and high-vigor scattered distribution.There was a positive correlation between the standard deviation of vitality and the intensity of vitality,that is,the areas with high vitality values had great changes in vitality throughout the day.(2)By comparing the areas of activity intensity of working days and rest days,it is found that the areas of high heat,secondary heat and relatively hot in rest days are all larger than those in working days,while the area proportion of general and ordinary activity intensity is just the opposite.The activity area of hyperthermia and subthermia was low in the day and high in the night.The activity area of common and ordinary types was high in the day and low in the night.However,the dynamic area of the hot type varies greatly between the working day and the rest day.(3)There are differences in the intensity of population activity between different functional Spaces and between the same type of functional Spaces.According to the intensity and balance of population activity,it can be concluded as follows:(1 the highly fluctuating type--business and office employment,commercial centers and large general hospitals;(2 the highly fluctuating type--transportation hubs,administrative and office employment and city-level commercial centers;and(3 the balanced type--residential areas and college education space.(4)Time difference exists in the explanatory power of the factors.The influence of weekday traffic factors and business and office factors in the daytime was significantly greater than that in the morning and night.The influences of consumption leisure factor,residential factor and floor area ratio factor in the daytime were significantly smaller than those in the morning and night.The fluctuation of the influence of each factor on rest day is relatively stable.(5)The results of interaction among all the influencing factors are double-factor enhancement,indicating that the urban vitality intensity is affected and restricted by all the factors in the urban built environment.At 11 o 'clock in the day,the core interaction factors of urban vitality intensity are commercial office facility density factor and floor area ratio factor.At 21 PM,the core interaction factors of urban vitality intensity are the density factor of consumption leisure facilities and the factor of floor area ratio,which indicates that the spatial differentiation of urban vitality intensity in the daytime and the night may be caused by the difference in the distribution of business office facilities and consumption leisure facilities.