Nonlinear relationship between urban form and transport CO_(2)emissions:Evidence from Chinese cities based on machine learning

Reducing carbon emissions from the transport sector is essential for realizing the carbon neutrality goal in China.Despite substantial studies on the influence of urban form on transport cO_(2)emissions,most of them have treated the effects as a linear process,and few have studied their nonlinear relationships.This research focused on 274 Chinese cities in 2019 and applied the gradient-boosting decision tree(GBDT)model to investigate the nonlinear effects of four aspects of urban form,including compactness,complexity,scale,and fragmentation,on urban transport CO_(2)emissions.It was found that urban form contributed 20.48%to per capita transport CO_(2)emissions(PTCEs),which is less than the contribution of socioeconomic development but more than that of transport infrastructure.The contribution of urban form to total transport CO_(2)emissions(TCEs)was the lowest,at 14.3%.In particular,the effect of compactness on TCEs was negative within a threshold,while its effect on PTCEs showed an inverted U-shaped relationship.The effect of complexity on PTCEs was positive,and its effect on TCEs was nonlinear.The effect of scale on TCEs and PTCEs was positive within a threshold and negative beyond that threshold.The effect of fragmentation on TCEs was also nonlinear,while its effect on PTCEs was positively linear.These results show the complex effects of the urban form on transport CO_(2)emissions.Thus,strategies for optimizing urban form and reducing urban transport carbon emissions are recommended for the future.

Spatiotemporal Differentiation of Urban Spatial Form and Carbon Emissions in Poyang Lake City Group

In response to the inherent requirements of low-carbon land spatial planning in Jiangxi Province and the lack of existing research,this paper explored the mechanism of spatial form elements of Poyang Lake urban agglomeration on urban carbon emissions.Based on generalized linear regression and geographically weighted regression models,this paper analyzed the spatiotemporal distribution characteristics of carbon emissions,the spatiotemporal relationship between urban form index and carbon emissions,and the spatial differentiation of the intensity of dominant factors from 63 county-level administrative units in the Poyang Lake city group from 2005 to 2020.The results showed that:①The carbon emissions of urban agglomerations around Poyang Lake are generally increasing,and the spatial distribution of carbon emissions is characterized by high-value concentration in the middle and low-value agglomeration in pieces;②The main driving factor for the spatial heterogeneity of carbon emissions was the expansion of built-up area;③Improving urban compactness and optimizing urban form could effectively reduce urban carbon emissions.The results showcased the correlation between urban spatial landscape pattern and the spatiotemporal distribution of carbon emissions,which could make the low-carbon land spatial planning in the Poyang Lake city group more reasonable and practical.

Urban Spatial Form Optimization Strategies Based on the Principle of Climate Adaptability of Regional Architecture: A Case Study of Traditional Cave Dwelling Villages in Northern Shaanxi Province

A multitude of climate-adaptive design approaches are embedded in regional architecture,which have a positive impact on addressing the deformed development of urban spatial patterns and the dual challenges of climate and resources.This paper examines the principles of climate adaptability embedded in the site layout and spatial organization characteristics of traditional cave dwelling villages in northern Shaanxi Province.The extracted climate adaptability principles are summarized,and the resulting design strategies that are well-suited to the contemporary urban space form are presented.Through analysis,it can be observed that traditional cave dwelling villages in northern Shaanxi are predominantly situated on south-facing slopes in proximity to water at low altitudes.These villages are characterized by compact building groups and east-west development,which is constrained by the elements of mountains and rivers.A two-level street system is generated,comprising streets parallel to the contour line and roadways perpendicular to the contour line.This results in the formation of a courtyard form enclosed by mountains.Such site layout and spatial organization exhibit excellent climate adaptability with regard to heat,ventilation,and wind storage.In light of the aforementioned considerations,the following urban spatial form design strategies are put forth:①the topographic height difference can be exploited to obtain sufficient sunshine;②the group shape can be optimized in order to reduce building energy consumption;③the best orientation of the building can be chosen to take account of both winter and summer conditions;④the height and length can be combined in order to form natural masking;⑤the D/H ratio of streets and roadways should be controlled to achieve a balance between heat gain and cooling of groups;⑥vents should be set appropriately to optimize group ventilation;⑦climate buffers should be established to increase the level of climate response.

Evolution of the“Golden Royal City”:Analytical study on urban forms of ancient capital cities in Myanmar

The historical cities in Southeast Asia with distinct characteristics are an important part of Asia’s cultural heritage system and the ancient capitals of Myanmar are as an example of these civilizational achievements.Their urban forms through history are essential spatial carriers reflecting the traditional local planning thinking.However,the overall understanding has yet to form due to a lack of systematic research.This study aims to complement it by studying the urban forms of almost all Myanmar’s ancient capitals based on verifiable spatial elements,works of literature,archaeology documents and field survey.The location,boundary and layout elements are analyzed to classify and characterize these urban forms,and their evolution rules are then summarized.Furthermore,the urban planning characteristics are discussed,indicating that the regulated structure and distinctive image gradually formed,accompanied by increasingly mature planning thinking and methods.The study reveals that the urban form and the planning thinking of Myanmar’s ancient capital cities had undergone an evolution with its own characteristics and that the“Golden Royal City”is of unique value in the genealogy of Asian capitals.The findings will contribute to the mutual learning between civilizations and provide a scientific foundation for the heritage conservation.

Urban Dynamics and Emergence of New Centers in the Dakar Region (Senegal)

Due to the status of the Dakar region as the former capital of AOF (French West Africa) and current capital of the Republic of Senegal, it is home to a very large part of the population and most of the socio-economic, administrative and cultural activities on a very small area of the country (0.28%). This situation makes it a very attractive region and subject to strong land pressure. The objective of this article is to study past and current urban dynamics as well as changes in natural spaces, in order to identify new urban centers. The methodological approach consists in analyzing satellite images to understand the evolution of different forms of spatial occupation in the Dakar region, and to study population movement flows and urban forms in order to reveal new urban centers. The results of the study show that the Dakar urban space is characterized by diverse forms which express a heterogeneous set of spaces. They also revealed the emergence of new clusters between 1986 and 2016, notably Ngor, Grand Yoff, Parcelles Assainies in the North-West, and Keur Massar and the North of the communes of Rufisque in the eastern part of the Dakar region.

Realizing the Box-counting Method for Calculating Fractal Dimension of Urban Form Based on Remote Sensing Image

In the research of fractal cities, the fractal dimension is very important. It is used to describe the fractal character of the city. The authors have designed two approaches to calculate the fractal dimension by the box-counting method through an example of Beijing, which are called the vector method and the grid method, respectively. The former calculates the fractal dimension through an intersecting analysis in ArcView; and the latter is carried out by programming in Matlab. They are compared from three aspects： the calculating process, the limits in use, and the results. As a result, the conclusion is made that there are merits and faults on both methods, and they should be chosen to use properly in practical situation.

Spatial investigation of the temporal urban form to assess impact on transit services and public transportation access

The rapid urban growth in developing city increases the requirement of the efficient and sustainable public transportation system.The urban growth affects the urban form,which indicates the change in human and urban development activity.Urban form affects directly and indirectly access to the public transportation system as an assessment of potential riders and proximity to stops increase transit services users.Therefore,access is one of the important aspects for the assessment of transit service efficiency.Public transportation access can be represented by a coverage area and useful to estimate potential riders of public transportation.In this study,a Geographical Information System(GIS)-based spatial statistical analysis method is used to examine the spatial relationship of different urban form indicators with population or riders of transit service in a coverage area and to ascertain how urban form influences public transportation trips in this coverage area.The coverage area is delineated using a GIS-based road/street network distance approach.The spatial analysis results suggested that urban forms have certain impact on trips in coverage area at both ward level and zone level.The statistical analysis implies that significant and positive values of spatial lag coefficient indicate a positive spatial interaction between wards and variable like total coverage area;worker density have shown positive and significant effects on trips of public transportation.

Construction of a refined population analysis unit based on urban forms and population aggregation patterns

The population analysis unit(PAU)is the basic unit employed in studies of urban populations.The commonly used PAUs are mostly administrative divisions,regular geographic grids.However,these units are different from urban forms,and cannot be used to consider the characteristics of population distributions and flow changes.In this study,we proposed a method for constructing a fine population analysis zone(FPAZ)based on the population aggregation pattern and urban form elements.First,considering the spatial structure of a city and the fine-grained demands of population analysis,the basic analysis unit was divided according to the functional heterogeneity of the population activity region at the micro-scale by combining urban form elements.Next,a population aggregation preference model was established by considering the spatial distribution characteristics of the local aggregation of the urban population flow and long-term stability characteristics depending on the dynamic changes in entrances and exits.Finally,we divided the FPAZ combined with the microstructural elements.Experimental results showed that compared with other types of PAUs,the FPAZ was more consistent with the urban morphology and was an appropriate and general spatial unit for expressing the accurate characteristics of population distributions and changes at the micro-scale.

A novel unsupervised deep learning method for the generalization of urban form

Accurate delineation of urban form is essential to understand the impacts that urbanization has on the environment and regional climate.Conventional supervised classification of urban form requires a rigidly defined scheme and high-quality sample data with class labels.Due to the complexity of urban systems,it is challenging to consistently define urban form types and collect metadata to describe them.Therefore,in this study,we propose a novel unsupervised deep learning method for urban form delineation while avoiding the limitations of conventional super-vised urban form classification methods.The novelty of the proposed method is the Multiscale Residual Convolutional Autoencoder(MRCAE),which can learn the latent representation of differ-ent urban form types.These vectors can be further used to generalize urban form types by using Self-Organizing Map(SOM)and the Gaussian Mixture Model(GMM).The proposed method is applied in the metropolitan area of Guangzhou-Foshan,China.The MRCAE model along with SOM and GMM is used to generalize the urban form types from satellite images.The physical and functional properties of each urban form type are also analyzed using several auxiliary datasets,including building footprints,Points-of-Interests(POIs)and Tencent User Density(TUD)data.The results reveal that the urban form map generated based on the MRCAE can explain 55%of the building height distribution and 55%of the building area distribution,which are 2.1%and 3.3%higher than those derived from the conventional convolutional autoencoder.As the information of urban form is essential to urban climate models,the results presented in this study can become a basis to refine the quantification of urban climate parameters,thereby introducing the urban heterogeneity to help understand the climate response of future urbanization.

Impact of Urban Form on Household Carbon Emission: Case Studies on Some Neighborhoods

Based on 1,400 pieces of questionnaires collected in Beijing, this study applies LISA to identify the spatial clustering households with high and low carbon emissions, and explores the relationship between household carbon emissions and urban forms via intensive case studies on five neighborhoods. Results indicate that all of building density, land use pattern, employment accessibility, and public transportation accessibility influence remarkably on household carbon emissions, which suggests that the rational planning of urban form is necessary for the construction of low-carbon cities.

A New Interpretation in Urban Form of the Wards of Tang Chang'an

By comparing the gridiron plans of ancient western cities with that of Tang Chang'an in the same scale,the authors find that a residential ward of Tang Chang'an was about the same size as an ancient western city.Thus the paper puts forward a hypothesis that Tang Chang'an was not a single city,but a cluster of hundreds of small towns with rigid layout.This theory is then proved by comparing a ward of Tang Chang'an with a typical small town in China from the perspectives of town scale,spatial layout,residential density,and land-use.The authors further explain the main cause for this unique urban form of Tang Chang'an,which was the compulsory migration policy.

跨学科视野下的城市设计——向丹尼斯·斯科特·布朗学习

丹尼斯·斯科特·布朗作为现代城市设计领域的杰出学者和实践者,以其独特的跨学科视角和对社会可持续发展的关注而闻名。本文通过回顾她的研究项目、学术著述和职业实践,分析其跨学科城市设计思想与方法,厘清布朗的学术贡献,并试图从中汲取启发,丰富我们对城市设计的理解和实践,创造出更加人性化和可持续的城市环境。

京杭大运河沿线主要城市空间形态的综合测度研究

京杭大运河作为连接中国南北地区之间的经济、文化发展与交流的走廊,历来对促进沿河城市兴起与繁荣发挥着关键作用。研究选取京杭大运河沿线8个主要城市的空间形态进行对比研究,利用空间句法对城市空间网络进行解构,并分析各个城市内部结构的不同之处;运用城市分形维数和紧凑度指数对不同城市进行计算,对城市空间外部形态特征进行分析;并将这些城市分为城市空间形态简单、城市空间形态较复杂和城市空间形态复杂三大类。最后根据分析结果提出针对性的城市发展建议,以期为大运河沿线城市以及此类其他沿河城市的空间形态发展提供参考。

先秦时期城市形态研究

中国传统城市模式具有深刻的哲学底色和文化内涵,但随着对营城建制的不断关注,主要的研究成果却集中在秦汉及之后的王朝时期,先秦时期城市发展尚未得到重视。该文将先秦城市作为研究目标,致力于探究先秦城市形态发展的整体趋势。先秦城市形态分为对称式和非对称式两种,并分别辨析不同形态出现的具体原因,继而指出两种形态间的关联系时代变化下城市职能转变所致。最后通过对现有城市遗址归纳整理,得出先秦城市形态以对称式为主,非对称式为辅的结论。

南京河西鱼嘴核心区城市设计中的一体化形态建构与管控

在新城核心区设计中,如何基于自然与人工资源特征进行形态整合往往是实现集约化开发的重要抓手。而在实施管控的过程中,通常会经历专题论证、实践反馈和动态调整的过程。以南京河西鱼嘴核心区为例,回顾其规划历程,总结其在滨江城市环境形态建构与管控中的关键策略,为当代中国高密度核心区的城市建筑一体化开发提供参考。

基于城市职能的明清金州古城景观格局之发展演变研究

金州古城地处辽东边陲,其城市平面和功能布局既受到军事防御功能的影响,又体现出儒家礼制的特征。古城空间格局在明代已初具规模,又经清代的建设与发展,形成了较为成熟的城市功能和完善的道路体系。将历经时代变迁的金州古城三维城市肌理变化以二维方式来进行体现,通过对明清两代古城空间结构与营建特点的介绍,直观感受城市空间与职能的发展和演变,进而对金州古城空间形态、功能区域以及城市职能转变的推动力进行了解析,并阐释了城市发展的动因。

基于产业转型升级的城市空间形态演变——以蛇口工业区为例

在深圳产业转型升级的背景下,城市的空间形态逐渐发生变化。深圳产业由最初的低技术、低成本制造业向高技术、高效益的高科技产业和服务业转型升级。其城市形态也由以制造业工业园区为主导的高密度和低容积率的空间形态,向产城一体化综合开发的低密度和高容积率的空间形态转变。深圳产业空间的城市形态演变规律的研究探索对于其他地区的发展有重要价值。深圳蛇口工业区在特区成立的40年内,经历了产业转型的过程。本文选取蛇口工业区为研究对象,基于城市形态学的理论和方法,从整体城市形态和城市街区形态层面上对其展开研究,分析功能、路网、绿地和岸线变化下的城市发展特点,探究区位、容积和覆盖率对街区形态的影响,并总结了产业转型升级下城市和街区的空间形态演变模式,研究结果可以作为产业转型升级的模式推广发展。

高密度城市人口动静集聚与街坊形态关联解析——基于曼哈顿的实证

高密度城市中人口具有高度流动性,其动静态人口的集聚现象和城市空间形态之间存在着一定程度的关联性。本文以曼哈顿为例,回溯其城市建设与形态演进轨迹,基于当前市域范围内静态和动态人口数据,运用空间聚类分析和曼哈顿人口探索器,识别出人口密度的空间分布特征。然后分别选取两个动、静态人口密度集中的1 km×1 km城市地段切片,通过空间矩阵分析其中典型街坊形态的量值特征,结果发现4个地段的形体密度存在梯度分异格局,并且与人口动静态分布的差异化现象相关。在此基础上,辨识并抽象出高密度街坊的组构类型,并揭示构成影响城市形态的隐性秩序和关联因素,最后提出曼哈顿城市形态对我国高密度城市建设的三点启示。

形态演变和驱动发展:天津城市空间拓展与影响因素研究

我国的城市发展已由增量扩张转为存量优化,通过对处于稳定发展阶段城市的空间形态和拓展因素的研究,有助于挖掘城市发展的规律特征,对未来的城市规划和城市更新起到引导和调控作用,促进城市转向高质量可持续发展。文章以天津市为例,以1985—2020年的城市遥感影像数据为基础,利用GIS工具对天津的城市扩张进行定量化和可视化分析,并通过逻辑回归(logistic regression)的方法,利用社会经济数据对影响城市发展的因素进行定量化研究,以探寻城市扩张的规律和驱动因素,为城市的更新发展探寻方向。

天津市中心城区典型城市形态原型中建筑形态的热环境效应

以天津市中心城区为例,使用Landsat-8遥感影像反演地表温度(LST),以表征城市热环境。同时,采用建筑数据量化17种建筑形态指标,并识别9种典型城市形态原型。在此基础上,分析不同城市形态原型间的地表温度差异,并用多元线性逐步回归方法探究不同城市形态原型中建筑形态的热环境效应。结果表明:①不同城市形态原型之间的夏季地表温度差异显著,低层高密度区地表温度均值最高,高层低密度区最低;②不同城市形态原型中建筑形态对夏季地表温度均有显著影响,但影响程度存在差异;③不同城市形态原型中各建筑形态因素对夏季地表温度影响方向一致,但重要性存在差异。因此,城市开发和更新中应关注城市形态模式和建筑形态,提出因地制宜的建筑形态调控策略。