Spatial Quality, Urban Vitality and Place Evaluation

Public space quality is a multidimensional concept. Urban design quality and physical disorder represent it from the perspectives of design and maintenance, respectively. However, the practical relationship between these two factors remains unclear, raising questions about the necessity of measuring multiple dimensions of public space quality simultaneously. Based on classical studies and theories, this study developed index systems for both factors. Utilizing arti ficial virtual auditing and deep learning models, including FCN and SegNet, the street visual quality of two Chinese cities was assessed from the perspectives of urban design and physical disorder using extensive street view images. The correlation between these two factors was explored. The results showed that the Spearman correlation coef ficients for urban design quality and physical disorder were 0.308 and /C0 0.085 in the two cities, respectively, indicating weak or unclear correlations. Addi- tionally, the fit and explanatory power of the linear and nonlinear regression models constructed were poor, further demonstrating that it is dif ficult to predict and explain one variable using the other. In the robustness test, the results were further validated by including control variables related to urban vitality, cultural characteristics, and urban development, considering the impact of the distribution of the street view images, drilling down to more granular dimensions and extending the scope of the study to a wider area. The levels of design and maintenance of streets cannot be conflated or substituted, and neither can independently represent the overall space quality alone. Both are indispensable, making it crucial to separately assess and address space quality issues from different perspectives. These results broaden our understanding of high-visual-quality street space and provide references for urban planners and stakeholders in improving street space quality. Corresponding author: Ying Long, School of Architecture and Hang Lung Center for Real Estate, Key Laboratory of Ecological Planning & Green Building, Ministry of Education, Tsinghua University, Beijing 100084, China. Email: ylong@tsinghua.edu.cn Data Availability Statement included at the end of the article

Principles of dense, mixed-use environments and pedestrianisation are influential in urban planning practice worldwide. A key outcome espoused by these principles is generating “ urban vitality ” , the continuous use of street sidewalk infrastructure throughout the day, to promote safety, economic viability and attractiveness of city neighbourhoods. Vitality is hypothesised to arise from a nearby mixture of primary uses, short blocks, density of buildings and population and a diversity in the age and condition of surrounding buildings. To investigate this claim, we use a novel dataset of 2.1 million time-lapsed day and night images at 145 representative locations throughout the city of Accra, Ghana. We developed a measure of urban vitality for each location based on the coefficient of variation in pedestrian volume over time in our images, obtained from counts of people identified using object detection. We also construct measures of “ generators of diversity ” : mixed-use intensity, building, block and population density, as well as diversity in the age of buildings, using data that are available across multiple cities and perform bivariate and multivariate regressions of our urban vitality measure against variables representing generators of diversity to test the latter ’ s association with vitality. We find that two or more unique kinds of amenities accessible within a five-minute walk from a given location, as well as the density of buildings (of varying ages and conditions) and short blocks, are associated with more even footfall throughout the day. Our analysis also indicates some potential negative trade-offs from dense and mixed-use neighbourhoods, such as being associated with more continuous road traffic throughout the day. Our methodological approach is scalable and adaptable to different modes of image data capture and can be widely adopted in other cities worldwide. ☆ This article is part of a special issue entitled: ‘ImageryAnalytics4UndHUI2 ’ published in ISPRS Journal of Photogrammetry and Remote Sensing. * Corresponding author at: Michael Uren Hub Building, 86 Wood Lane, London W12 0BZ, UK. E-mail address: r.nathvani@imperial.ac.uk (R. Nathvani). 1 Senior author. Contents lists available at ScienceDirect ISPRS Journal of Photogrammetry and Remote Sensing journal homepage: www.else vier.com/loc ate/isprsjprs https://doi.org/10.1016/j.isprsjprs.2025.01.038 Received 26 June 2024; Received in revised form 25 January 2025;

Transit-oriented development (TOD) is regarded as urban planning concept of integrating urban land use and transportation networks. Previous stud- ies on TOD indicators and their impacts on shifting trip modes have been en- riched, while quantitative analysis of the relationships between specific indica- tors of TOD principles and urban vitality remains limited. Therefore, we pro- posed a three -step framework to conduct a nationally large -scale analysis as- sessing the relationship of TOD with urban vitality, which was applied in 35 cit- ies with 3,273 subway stations in China. The results show that (1) TOD principles are significantly relevant to urban vitality, (2) stations closer to the city CBD, with dense roads, buildings, parks, and walkability are more vibrant, and (3) more complexity of functionalities will be detrimental to offline con sumption activi- ties. The results and suggestions may serve as references for enhancing urban planning and policies in China and other developing nations, thereby promoting worldwide sustainable development.

In this study, we focus on the quality of street space which has attracted high attentions. We discover associations between the quality of street space and built environment attributes through an ordered logistic model using massive street view pictures (SVPs) and data on street location, form, function and attributes. Before ascertain which built environment factors influence the quality of street space, we checked the concordance of the experts’ scores, as well as correlations between different dimensions through Kappa analysis and drew the distribution map of street space quality. We found that the value of intersection over union is 85.61% for scoring the street space quality by different people. The spatial quality of more than 75% streets are in the middle level with no obvious polarisation observed in the central area of Qingdao. In addition, for street quality index, all variables are statistically signi ficant. The sequence is as follows: near-line rate > D/H ratio > slope > length of street > distance to administrative center > POIs diversity. The D/H ratio, near-line rate, slope length of street, distance to administrative center and POIs diversity have various associations on every dimension of street quality. They can prove useful for drafting more appropriate policy measures aimed at improving street quality. #Joint first authors, these authors contributed equally to the work Corresponding author: Ying Long, School of Architecture and Hang Lung Center for Real Estate, Tsinghua University, 1 Qinghuayuan, Beijing 100084, China. Email: ylong@tsinghua.edu.cn

Small public spaces are important for citizens to live and socialize with a high utilization rate. The vitality of small public space plays an important role in evaluating space quality and attraction and provides reference for urban governance issues such as vitality evaluation of public space, quality optimization, and site micro-renewal. Previous studies of vitality based on low-throughput surveys or big data with low positioning accuracy are not suitable for the high-efficiency study of small public space. In this study, a systematic framework of vitality quantification in small public spaces is built on fine-grained human trajectories extracted from videos for more efficient and refined human-oriented vitality evaluation. A multi-indicator vitality quantification method is first proposed to comprehensively represent human vitality, including number of people, duration of stay, motion speed, trajectory diversity and trajectory complexity. Furthermore, a video dataset of small public space along with our sub-index-assisted expert assessing scheme is proposed to evaluate our vitality quantification frame - work. Finally, we analyze the correlation between quantitative vitality indicators and the expert-assessing vi - tality through multiple linear regression and obtain the optimal vitality quantification model. The experimental results indicate that our dataset is reliable and the vitality quantification model constructed with our quantitative indicators can better characterize urban vitality than the previous model based on number of people and staying time.

People and their activities are the core of the vitality of urban public space. The measurement of public space vitality focusing on people and their activities has always been a difficulty in human-scale urban researches. In view of the representation of public space vitality, this research proposes a new method of spatial vitality representation based on the crowd trajectory clustering. In this method, the multi-object tracking technology based on videos is used to extract the trajectory of the crowd, which is further clustered based on the trajectory structure. According to the diversity of trajectory categories and the difference of structures, “the space trajectory entropy” is put forward to reflect the diversity and mixing degree of the behavior patterns in public space, and to measure the complex state of crowd activity from a novel and concise perspective, so as to represent the vitality of public space. In this research, three public spaces in Wuhou District of Chengdu City are selected as the research objects. The spatial trajectory entropy of the three scenes is calculated under this method. Combined with manual review, it explores the changes and causes of the time series of spatial vitality of the three scenes and gives spatial optimization suggestions. The results show that the spatial vitality characterization method can objectively describe the temporal and spatial movement of the crowd, precisely reflect the spatial-temporal vitality of space, reflect the exact urban operation and maintenance reality in the space, and contribute to establish a human-scale dynamic evaluation mechanism of spatial vitality. As a result, the proposed work can provide precise technical support for city governance, such as public space vitality assessment, quality optimization and site micro-renewal.

Summarizing the international housing appearance space quality assessment tools, combined with the local background of China, this paper constructs the index system of the appearance space quality of Chinese residential areas, and objec - tively assessments the appearance space quality of 273 residential areas in the central urban area of Pingdingshan by using the video / image data of residential areas from Anjuke and the virtual audit method, so as to lay a foundation for the follow-up related research. 关键词：居住区；外观空间质量 ; 安居客 ; 虚拟审计 ; 平顶山

The spatial factors that affect urban vitality are complex and diverse. There is no consensus in existing studies, and there is a lack of summary and verification. Through systematic review and empirical research, the spatial factors affecting urban vitality are explored. Relevant empirical studies are searched and screened in Web of Science Core Collection. Common indicators representing urban vitality and spatial factors affecting urban vitality are summarized, including research scale, specific indicators, occurrence frequency, and Impact properties. The local empirical research takes the downtown area of Linyi as the research scope and the block as the research unit. It uses Weibo check-in data, POI (Point of Interest) data and night light data to measure the urban vitality, and measures 16 spatial factor indicators to establish an econometric model to analyze the correlation between spatial factors and urban vitality. The results show that the spatial factors affecting urban vitality are mainly divided into six categories: road traffic, block pattern, land use, architectural characteristics, accessibility and boundary vacuum. The convenience of transportation, the degree of land mixing and development intensity, and the relative location of research units are all important factors affecting urban vitality. The research results are helpful to understand the specific performance of vibrant urban space. It provides theoretical basis and practical reference for relevant research, and provides theoretical support and optimization direction for improving vitality oriented urban construction. 关键词 ：空间要素 ； 建成环境 ； 街区 ； 大数据 ； 量化评价

Online activities based on various social media applications are gradually becoming a vital social activity issue in the mobile Internet era. This study aims to reveal the spatial preferences embedded in this new type of urban life to better plan and design future cities. With two different types of social media data—online loca- tion tagging from Weibo and online reviews of POIs on Dianping—we conducted a quantitative analysis to explore the relationship between online activities and the built environment elements. The results suggested that online activities remain associated with urban entities, and the activity represented by Dianping reviews revealed more significant spatial preferences than that described by Weibo check-ins. The results also showed similarities and differences between spatial choices of those who engage in these two activities. These findings allow for an in-depth understanding of contem- porary cities’ complexity and provide new opportunities for integrating cyberspace and city space.

In recent years, space quality and design of streets have received increasing attention. In the field of public health, the insufficient quality of urban spatial characteristics or even disorder have been proved to directly or indirectly affect the physical and mental health of individuals, implying high-risk influence on individual behavior and delivering negative health outcomes. The improvement of micro-scale spatial features is beneficial to enhancing the activity-friendliness of public space and shaping positive psychological perceptions, thereby promoting public health. Focusing on the core goal of creating high-quality urban street space, this study takes the street space of the public space as the research object, and pays attention to the phenomenon of insufficient local space quality. Based on the current quality and significant characteristics of street space quality in China, it sorts out relevant design strategies in various street design guidelines for cities at home and abroad, and proposes design response strategies for different space quality factors, so as to explore the practical points to solve the problem of poor street space quality or physical disorder in Chinese cities, to pave a way for public health-oriented environmental maintenance, improvement and organic renewal, and to further serve the refined urban space management and design.

The influence of urban design on economic vitality has been analyzed by a number of researchers and is also a key focus of many planning/design theories. However, most quantitative studies are based on just one city or a small set of cities, rather than a large number of cities that are representative of an entire country. With the increasing availability of new data, we aim to alleviate this gap by examining the impact of urban design upon economic vitality for the 286 largest cities in China by looking at a grid of geographical units that are 1 km by 1 km. We use these units and a set of new data (emerging big data and new data that reflecting urban developments and human mobility) to look at the impact of urban form indicators, such as intersection density (urban design), level of mixed use, and access to amenities and transportation, on economic vitality represented by activities using social media data. Our results show that these urban design indicators have a significant and positive relationship with levels of economic vitality for cities at every administrative level. The results contribute to a holistic understanding of how to improve economic vitality in cities across China at a detailed level, particularly at a time when China’s economic growth will depend largely on growth of the service sector in urban areas. We think these results can help decision makers, developers, and planners/ designers to improve economic vitality in cities across China.

Although it is widely known that quality of street space plays a vital role in promoting urban vibrancy, there is still no consensus on how to quantitatively measure it for a large scale. Recent emerging dataset Street View Picture has revealed the possibility to overcome the previous limit, thus bringing forward a research paradigm shift. Taking this advantage, this paper explores a new approach for visual quality evaluation and variation identification of street space for a large area. Hutongs, which typically represent for historical street space in Beijing, are selected for empirical study. In the experimental part, we capture multi-years Tencent Street View Picture covering all the Hutongs, and conduct both physical and perceived visual quality evaluation. The physical visual quality of street space is achieved automatically by combining 3-dimensional composition cal- culation of greenery, openness, enclosure using machine-learning segmentation method SegNet, and 2-dimen- sionalanalysisofstreetwallcontinuityandcross-sectionalproportion;perceivedvisualqualityofstreetspaceis evaluated by stay willingness scoring from five aspects. The variation of quality is evaluated based on the identified physical space variations. The result indicates that visual quality of Hutongs are not satisfied, while some regeneration projects in the historical protection block is better. Most Hutongs are in shortage of visual green,relativemorecontinuousbutwithlowcross-sectionalratio.Hutongsnearmainroadwitnessanincreasing trend of motorization. The difference between physical and perceived quality indicates the feasibility and lim- itation of the auto-calculation method. In the most recent 3–4years, less than 2.5% Hutongs are improved, which are mainly slow beautification.

The new normal era witnesses the policy shifting from growth planning to quality management. It is in urgent need to carry out the scientific assessment and quantitative research on the built environment. As street is an important public domain, its quality and vitality become one of the major research directions. Focusing on street space, this paper analyzes the existing quantitative approaches of street space in China and abroad from three aspects: the concept of street space quality, the large-scale quantification method, and the measurement method of street space quality. In conclusion, there are a number of measurement approaches for physical street space in various aspects, but the integrated application of the approaches is limited. It is a new research direction in the world to use street view pictures with high availability to conduct street space measurement. The influencing mechanism of the quality and vitality of street space still requires in- depth research, and the discussion about scientific research-based street planning and design methods is lacked in existing studies.

Vitality is the important indicator to evaluating the quality of urban space. The factors impacting the vitality are different in various periods of one day. Focusing on streets, the significant urban public space, this paper chooses nights, the special period, and combines the field research and quantitative evaluation to conduct a quantitative evaluation and correlation study of the night vitality of streets and its impact factors within the 2nd-Ring Road of Beijing. The research indicates that the street forms and functions affect its night vitality significantly, while the accessibility has no obvious influence. Based on the results of the research, the paper puts forward the corresponding suggestions on the planning and design.

笔者自1998 年来北京求学，在北京已有二十载，这个城市留给我最深刻印象的是它的街道、广场和公园绿地等公共空间，我的日常生活和城市记忆——位于北京站前广场的清华大学接待站让下了火车初来北京的我时时回味，在南礼士路公园的多次午后散步，邂逅那些熟悉的陌生人——多发生在北京的公共空间。作为城市空间最为核心的要素之一，公共空间不仅承载了包括我在内的人们的生活与记忆，也是感受一座城市的精神的重要场所。 一座城市公共空间的“好”与“坏”也经常为居民与游客津津乐道。 最近的诸多会议和文件都明确提出要把提高城市公共空间品质提到日程上来，公共空间的品质直接关系到一个城市的规划建设和管理水平，并影响着居民的生活质量，对其进行深入研究具有深刻意义。空间品质（quality of space）是反映城市人群对城市空间综合需求形成的评价概念，其作为空间的总体质量，反映了城市空间各组成要素在“量”和“质”两方面， 对城市人群和城市社会经济发展的适宜程度。空间品质的综合性导致了界定和测度的困难，已有研究多以质性研究为主。 在城市公共空间品质及其提升被不断重视的背景下，信息与通信技术 （Information and Communication Technologies，ICT）通过对人们生活方式的改变，进而对城市公共空间产生巨大的影响。在中国快速城市化与 ICT技术迅速发展的交叉口，无论是中国城市公共空间的物质空间还是所承载的城市生活都发生了巨大变化。 这样的背景对已有的相关研究发现提出了挑战，也给未来研究提供了新需求。当前涌现出的一系列新的数据环境、技术及方法为城市公共空间研究提供了新途径。例如，由大数据和开放数据构成的新数据环境使更好地从物质空间和社会空间刻画街道空间成为可能，雷达成像、脑电波、眼动仪、机器学习、大数据挖掘与可视化等先锋城市研究方法和技术也不断成熟。这些为城市公共空间的测度、空间品质与活力的评价，以及影响机理的研究提供了新的机遇。 在此背景下，本专辑旨在就基于新数据、新技术的城市公共空间品质提升研究这一主题进行多视角的初步探讨。经过遴选和评审，共 8 篇文章被选入本专辑。（1）同济大学的怀松垚、陈筝和刘颂首先为这一方向撰写了全面系统的综述文章 ； （2） 清华大学的李智和龙瀛提出了利用多年的街景图片数据对街道空间品质变化进行探测的方法并应用于对收缩城市齐齐哈尔市的研究；（3）华中科技大学的贺慧、陈艺和林小武则以武汉的两条商业街道为例，对街道公共空间品质的影响因素进行了识别；（4）厦门大学的张晶、李渊和王燕飞探讨了面向品质改善的街道空间设计方法，并应用于对厦门鼓浪屿的福州路和鼓新路的研究 ； （5）北京交通大学的刘星、盛强和杨振盛对利用街景地图这一新兴数据源分析街道空间活力的适用性进行了评估 ； （6）北京林业大学的刘祎绯和美国佐治亚理工学院的薛博文合作的文章则从声音景观视角对北京五道口片区的开放空间品质进行现状评估，并提出了设计优化思路；（7）北方工业大学的杨鑫、贺爽和卢薪升从热舒适性角度，基于软件模拟方法对北京白塔寺片区 6 条胡同的空间品质进行评测；（8）北京工业大学的熊文、阎伟标、刘璇和马瑞利用人本观测方法对北京历史街道进行了持续观测，进而提出了其空间品质的提升路径。 文章成稿后，2017年12月25日编辑部在清华大学建筑学院举行了同主题的主题沙龙，专辑部分作者参加了沙龙并进行了深入研讨，并根据研讨内容进行了必要的论文修改。 城市公共空间品质提升研究本期客座主编 ： 龙瀛清华大学建筑学院副教授，特别研究员，博士生导师

As a primary public space in city, street not only bears the important function of commerce, but its spatial quality is also highly influential on districts’ cultural styles and features. Under the circumstances of rapid comm ercialization in China recently, one significant responsibility of urban planning is exactly to handle the relationship between commercialization and historical district protection. Focused on an empirical study o n Dongsi historical d istrict in Beijing, this article builds an evaluation mechanism of streets’ spatial quality and guidelines for street interface design based on theories like “Time–Space–People” model. With the application of big data such as multi -temporal and multi -angle Street View images a nd POIs, it is feasible to evaluate the status quo and the variance of spatial quality of streets in Dongsi, and its relationship with the commercialization occurring in such a historical district. The conclusions drawn from the measuring methods mentioned above are as follows : on one hand, generally the status quo of streets’ spatial quality in Dongsi is good, though the score varies with different streets (or synonymous Hutongs), and the interface of commerce varies with different types of operation. On the other hand, the streets in Dongsi see an obvious change in the interface between 2013 and 2016, whos e range of change is even larger than the average range of whole Beijing, yet the effective changes are relatively rare , indicating the necessity of guidelines for street interface design . Moreover, among the different kinds of street interface, commercial interface is the one with the largest range of change and the most effective changes. The expected result s of this article is to summarize the condition of spatial quality of streets in Dongsi historical district and to further develop some systematic guidelines for street interface design, which can not only be applied to Doingsi itself but also to other historical districts. Therefore, it will guide the orderly introduction of co mmercial activities into historical districts while maintaining its unique cultural style and features. 2

] 街道空间品质影响着人的行为习惯、 公共健康水平和城市文化的塑造。 为了进一步深化已有的街道空间品质研究， 提升特大城市街道环境品质，文章引入街道空间品质量化评价方法，利用街道微观尺度的图像数据，通过要素客观构成分析和使用者主观评价，对北京和上海的街道空间品质进行了测度，发现两地的街道空间品质整体一般，尚需改善。 [

4 北京规划建设话题 THEME | 新数据环境下的城市：品质、活力与设计新数据环境下的城市：品质、活力与设计北京城市实验室（Beijing City Lab，BCL）成立于2013年10月，专注于运用跨学科方法量化城市发展动态，为更好的城市规划与管理提供可靠依据，最终建立起可持续城市发展所需要的方法学基础。BCL的研究主题以“新城镇化规划”中的人居环境质量为核心，希望对中国快速城镇化时期的人居环境质量进行全面的度量与监测，为国家决策提供依据和保障。 BCL坚持定量城市研究的创立理念，持续组织交流新数据环境城市研究在理论与实践上的最新实践。北京城市实验室年会作为其组织活动的重要组成部分，自2014年起每年举办，通过邀请海内外相关领域专家学者介绍学科发展的动态前沿，同时对海内外参会人员一律免费开放，从第一届实施北京规划建设 5 新数据环境下的城市：品质、活力与设计 | THEME 话题话题 | THEME 至今，受到社会各界的广泛关注与积极参与。BCL2016年会在北京清华同衡规划设计研究院举办，年会以“新数据环境下的城市：品质、活力与设计”为主题，聚焦新数据、新方法和新技术，关注城市空间品质与城市活力，就新数据环境下量化城市研究在理论与实践上的最新成果进行交流，对向全社会普及与强化以营造品质和活力为目的的城市规划设计有重要意义。本专辑收录了BCL2016年会的部分文章，旨在对“新数据环境下的城市：品质、活力与设计”这一主题进行初步探讨。 北京城市实验室（Beijing City Lab，BCL） 本刊编辑部