Study On The Measurement And Quantitative Evaluation Of Street Space Quality In Harbin Based On Street View Pictures

Urban street space,the most frequent place for users to cross,walk,rest and intercourse,as an important part of urban public space,reflects the cultural style of the city and the spiritual civilization of the society.As people’s material life is satisfied,cities and users are seeking to enhance street space quality.Harbin’s regional cultural characteristics are outstanding,but through field research and data collation,it is found that some of Harbin’s street spaces are in urgent need of optimization and transformation.On the basis of theoretical research,the line density,intersection kernel density and POI kernel density characteristics of Harbin’s street network are analyzed.We obtain street view pictures by Python and use semantic segmentation technique to identify each element of the street and its proportion.Based on this,a study is conducted to measure and evaluate the quality of Harbin’s street space and to identify the problems that exist in the street space.The main work and findings of the study are as follows.(1)The evaluation of urban street space quality is considered from both the objective physical space of the street and the subjective psychological feeling of pedestrians.The evaluation index system containing 4 first-level indicators and 12 second-level indicators is constructed by using AHP in combination with each element segmented from the street view pictures.A study is conducted to quantify and measure and evaluate the space quality of streets with 72 streets as examples,and found that the spatial quality of streets in Nangang District was better,followed by Daoli District,Xiangfang District,and Daowai District.High-quality streets have the advantages of richer vegetation,higher sky visibility,a wide variety of ground floor stores,and good transportation facilities.Low-quality streets have major problems in plant landscaping,sidewalk space design,and sense of street scale,such as obstruction by fences,insufficient construction of plant greenery,and clutter of street elements.The reliability of the evaluation model is verified by comparing the results of each street measure with the user satisfaction scores.(2)By analyzing the spatial characteristics of streetscape picture elements,the correlation between the indicators in the evaluation model and the street spatial quality measurement values,and the scatter plot fitting analysis,it is found that the six items of spatial green view rate,interface enclosure,motorization degree,street scale sense,traffic guidance degree,and the proportion of street light type facilities are significantly correlated with the changes of the street spatial quality measurement values.A comfortable sense of scale,lush street trees and a safe walking environment are the externalized expressions of these high-quality streets such as Hengshan Road,Beixing Street,Central Avenue,Ganshui Road,Zhaolin Street and Civil Aviation Road.(3)The cross-correlation analysis among the evaluation indexes is used to discover the influence mechanism of street space quality.The evaluation indexes are divided into 4categories: comfort factor,function factor,safety factor,and service factor.Based on the combination of different indicators,five types of street space patterns are summarized:landscape comfort type,daily life type,crossing and passage type,shopping and service type,and comprehensive development type quality streets.In response to the above study,we propose a tiered optimization strategy to optimize the quality of street space in five aspects: street greening,street scale,street facilities,street feasibility,and street safety.The above,not only enriches the research perspectives and methods of urban street space quality,but also can guide the transformation and vitality reshaping of urban street space.