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 ...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.展开更多
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 d...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.展开更多
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 h...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.展开更多
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 s...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.展开更多
The urban heat island effect is a widespread phenomenon in major cities worldwide,exerting significant impacts on urban environments,human health,and energy consumption,thus attracting extensive research interest.The ...The urban heat island effect is a widespread phenomenon in major cities worldwide,exerting significant impacts on urban environments,human health,and energy consumption,thus attracting extensive research interest.The manifestation of the urban heat island effect varies across different urban forms.This study employs a three-dimensional porous media model to comprehensively analyze the urban heat island effect and the influence of wind speed on three typical urban layouts:single-center,multi-center,and grid.The results indicate:(1)The more dispersed the city center,the weaker the urban heat island intensity,with differences in peak heat island intensity of up to 0.3 K among different urban forms.(2)Under favorable environmental wind conditions,higher wind speeds lead to weaker heat island intensity.At v=5 m/s,the grid-based heat island intensity decreases by 0.57 K.(3)With increasing building density,the urban heat island effect intensifies in all three types of cities,with the single-center city exhibiting the largest increase in heat island intensity,up to 23.5%。展开更多
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 ur...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.展开更多
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 achievement...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.展开更多
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 c...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.展开更多
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 ci...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.展开更多
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 agglom...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.展开更多
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 ...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.展开更多
Air pollution has a serious fallout on human health,and the influences of the different urban morphological characteristics on air pollutants cannot be ignored.In this study,the relation-ship between urban morphology ...Air pollution has a serious fallout on human health,and the influences of the different urban morphological characteristics on air pollutants cannot be ignored.In this study,the relation-ship between urban morphology and air quality(wind speed,CO,and PM_(2.5))in residential neighborhoods at the meso-microscale was investigated.The changes in the microclimate and pollutant diffusion distribution in the neighborhood under diverse weather conditions were simulated by Computational Fluid Dynamics(CFD).This study identified five key urban morphological parameters(Building Density,Average Building Height,Standard Deviation of Building Height,Mean Building Volume,and Degree of Enclosure)which significantly im-pacted the diffusion and distribution of pollutants in the neighborhood.The findings of this study suggested that three specific strategies(e.g.volume of a single building should be re-duced,DE should be increased)and one comprehensive strategy(the width and height of the single building should be reduced while the number of single buildings should be in-creased)could be illustrated as an optimized approach of urban planning to relief the air pollution.The result of the combined effects could provide a reference for mitigating air pollution in sustainable urban environments.展开更多
Understanding the spatiotemporal patterns of three-dimensional urban forms,especially building height,can have important implications for improving urban air quality and mitigating the urban heat island effect by opti...Understanding the spatiotemporal patterns of three-dimensional urban forms,especially building height,can have important implications for improving urban air quality and mitigating the urban heat island effect by optimizing urban planning and management policies.This study investigated building height evolution and its influencing factors over approximately half a century(1960–2017)in Guangzhou,China.The results indicated that the logarithmic declines in height,quantity,and area of urban buildings followed Zapf’s law,which restricts the three-dimensional shape of the urban form.The urban building height decreased from the center to the periphery of the city and decreased with decreasing altitude and increasing distance from main roads.These characteristics constituted the three main spatial differentiation rules of building height in the central district of Guangzhou,and all exhibited a logarithmic decrease,which gradually strengthened over time.The development of a double-layered height structure of low-rise and high-rise buildings between 1990 and 2017 was a notable manifestation of the increase in vertical urban height over time.The three factors of city center,altitude,and accessibility,which represent centrality,low relief,proximity to water,and proximity to road networks,highlighted the roles of traffic accessibility and commercial attraction in building height evolution.The importance of location macroscopically depends on the combined effect of the geographical pattern,urban planning,and market forces of cities located on a plain near hill or by a river.The principle of profit orientation restricted spatiotemporal building height patterns.展开更多
Urban land density is an important factor to understand how cities expand.An“Inverse S-shape Rule”was implemented for the first time to analyze urban land density in Northeastern Thailand using the four cities Khon ...Urban land density is an important factor to understand how cities expand.An“Inverse S-shape Rule”was implemented for the first time to analyze urban land density in Northeastern Thailand using the four cities Khon Kaen,Udon Thani,Nakhon Phanom,and Nong Khai as study sites.Land density function was tested using different data classification techniques from previous studies.Each city was investigated over two different time periods between 2002 and 2015.Declining pattern characteristics of metropolitan area density outward from city centers can be quantified by fitting the parameters to urban land density functions.An inverse S-shape function was identified as the best data fit.The four selected cities showed conventional density variation for decline in urban land area from city centers to outlying areas.Overall trend indicated that cities became more compact over time since the density differences between the urban core and urban fringe were greater with increasing infilling growth within the urban boundary.All four cities increased in size over time;however,the increasing amount of built-up land in the surrounding rural areas did not follow the same trend in each case.Some functional parameters required careful interpretation because of the linear shape of the city as in the case of Nakhon Phanom.Using highly detailed urban data resulted in lower densities of urban areas compared to the conventional pixel-based classification,and this affected the overall shape of the inverse S-shape function.The fitted parameters and their changing trends indicated that the urban land density function was useful for understanding urban form and urban sprawl in Thailand.Results can be used to develop a specific framework for other cities with similar attributes in the future.展开更多
The present study analyzes the structure and dynamics of the forest landscape in a peri-urban area （Rome, Italy） during the city＇s expansion from 1949 to 2008 using landscape metrics and change detection anal- ysis...The present study analyzes the structure and dynamics of the forest landscape in a peri-urban area （Rome, Italy） during the city＇s expansion from 1949 to 2008 using landscape metrics and change detection anal- ysis of digital maps of the area （1500 km2）. While urban settlements increased continuously from 6.5 to 27.5 % of the study area, woodlands changed less clearly, with a moderate increase （from 11.2 to 11.9 % of the total area） and a higher fragmentation as a consequence of Rome＇s expansion. The structure of forest landscape changed along the urban-to-rural gradient with patch size increasing with the distance to the inner city in 1949 and substantial landscape homogeneity in 2008. The indicators proposed in this study inform dedicated measures for conserving forest and maintaining landscape diversity. Measures adopted in Rome＇s forestation plan to counteract woodlandfragmentation were analyzed and discussed. Based on the complex landscape dynamics found for Rome, an inte- grated multiscale planning approach targeting forest con- servation is considered a key contribution to urban sustainability.展开更多
The vertical distribution of air pollutants in urban street canyons is closely related to residents’health.However,the vertical air quality in urban street canyons has rarely been assessed using field observations ob...The vertical distribution of air pollutants in urban street canyons is closely related to residents’health.However,the vertical air quality in urban street canyons has rarely been assessed using field observations obtained throughout the year.Therefore,this study investigated the seasonal and annual concentrations of particulate matter(PM2.5 and PM10),CO,NO_(2),SO_(2),O_(3),air quality index,and their responses to microclimatic factors at three height levels(1.5,27,and 69 m above street level)in an urban street canyon.The PM concentration was higher at 27 m than at 1.5 m in winter,whereas the situation was reversed in other seasons.It was found that photochemical pollutants such as NO_(2) and O_(3) were the primary pollutants in the urban street canyon.The days on which O3 was the primary pollutant at the height of 1.5 m accounted for 81.07% of the entire year.The days on which NO_(2) was the primary pollutant at the height of 27 and 69 m accounted for 82.49% and 72.33%of the entire year,respectively.Substantially higher concentrations of NO2 and O_(3) were found at the height of 27 m than at 69 m.In-canyon concentrations of NO_(2) and O_(3) were strongly correlated with air temperature,wind speed,and wind direction,which played important roles in photochemical reactions and pollutant dispersion.展开更多
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,...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.展开更多
文摘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.
文摘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.
基金National Natural Science Foundation of China,No.42071227,No.42371214。
文摘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.
基金supported by the National Key R&D Program of China[grant number 2019YFA0607201 and 2017YFA0604401]the National Natural Science Foundation of China[grant number 41871306]+1 种基金the Guangdong Natural Science Funds for Distinguished Young Scholar[grant number 2021B1515020104]the Fundamental Research Funds for the Central Universities[grant number 20lgzd09].
文摘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.
基金supported by the National Natural Science Foundation of China(Grant no.52278123)CITIC General Institute of Architectural Design and Research(No.2022ZXKYD30100)the Scientific Research Foundation of the Wuhan University of Technology(Grant nos.40120237 and 40120551).
文摘The urban heat island effect is a widespread phenomenon in major cities worldwide,exerting significant impacts on urban environments,human health,and energy consumption,thus attracting extensive research interest.The manifestation of the urban heat island effect varies across different urban forms.This study employs a three-dimensional porous media model to comprehensively analyze the urban heat island effect and the influence of wind speed on three typical urban layouts:single-center,multi-center,and grid.The results indicate:(1)The more dispersed the city center,the weaker the urban heat island intensity,with differences in peak heat island intensity of up to 0.3 K among different urban forms.(2)Under favorable environmental wind conditions,higher wind speeds lead to weaker heat island intensity.At v=5 m/s,the grid-based heat island intensity decreases by 0.57 K.(3)With increasing building density,the urban heat island effect intensifies in all three types of cities,with the single-center city exhibiting the largest increase in heat island intensity,up to 23.5%。
基金supported by the National Natural Science Foundation of China(U20A2091,41771426).
文摘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.
基金the support of the National Natural Science Foundation of China(Grant Number 52078116)“Research on morphological characteristics,type spectrum and heritage value of historical capitals in Indochina based on multi-source remote sensing data”.
文摘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.
基金funded by the General Program of National Science Foundation of China (41001103),Australia Research Council (ARC P1094801)the project of Economics Discipline Group Construction in Capital Colleges and Universities (Beijing)
文摘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.
基金part of the research project No.50108002 funded by National Natural Science Foundation of China
文摘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.
基金by the 2022 National Natural Foundation of China(42261046)The 2021 Project for Humanities and Social Sciences of Jiangxi Higher Education Institutions(JC21237).
文摘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.
基金Sponsored by Beijing Urban Governance Research Base of North China University of Technology(2024CSZL07).
文摘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.
基金supported by the National Natural Science Foundation of China(No.51808009).
文摘Air pollution has a serious fallout on human health,and the influences of the different urban morphological characteristics on air pollutants cannot be ignored.In this study,the relation-ship between urban morphology and air quality(wind speed,CO,and PM_(2.5))in residential neighborhoods at the meso-microscale was investigated.The changes in the microclimate and pollutant diffusion distribution in the neighborhood under diverse weather conditions were simulated by Computational Fluid Dynamics(CFD).This study identified five key urban morphological parameters(Building Density,Average Building Height,Standard Deviation of Building Height,Mean Building Volume,and Degree of Enclosure)which significantly im-pacted the diffusion and distribution of pollutants in the neighborhood.The findings of this study suggested that three specific strategies(e.g.volume of a single building should be re-duced,DE should be increased)and one comprehensive strategy(the width and height of the single building should be reduced while the number of single buildings should be in-creased)could be illustrated as an optimized approach of urban planning to relief the air pollution.The result of the combined effects could provide a reference for mitigating air pollution in sustainable urban environments.
基金Under the auspices of National Natural Science Foundation of China(No.41771001)Science and Technology Planning Project Funds of Guangzhou(No.201704020136)。
文摘Understanding the spatiotemporal patterns of three-dimensional urban forms,especially building height,can have important implications for improving urban air quality and mitigating the urban heat island effect by optimizing urban planning and management policies.This study investigated building height evolution and its influencing factors over approximately half a century(1960–2017)in Guangzhou,China.The results indicated that the logarithmic declines in height,quantity,and area of urban buildings followed Zapf’s law,which restricts the three-dimensional shape of the urban form.The urban building height decreased from the center to the periphery of the city and decreased with decreasing altitude and increasing distance from main roads.These characteristics constituted the three main spatial differentiation rules of building height in the central district of Guangzhou,and all exhibited a logarithmic decrease,which gradually strengthened over time.The development of a double-layered height structure of low-rise and high-rise buildings between 1990 and 2017 was a notable manifestation of the increase in vertical urban height over time.The three factors of city center,altitude,and accessibility,which represent centrality,low relief,proximity to water,and proximity to road networks,highlighted the roles of traffic accessibility and commercial attraction in building height evolution.The importance of location macroscopically depends on the combined effect of the geographical pattern,urban planning,and market forces of cities located on a plain near hill or by a river.The principle of profit orientation restricted spatiotemporal building height patterns.
文摘Urban land density is an important factor to understand how cities expand.An“Inverse S-shape Rule”was implemented for the first time to analyze urban land density in Northeastern Thailand using the four cities Khon Kaen,Udon Thani,Nakhon Phanom,and Nong Khai as study sites.Land density function was tested using different data classification techniques from previous studies.Each city was investigated over two different time periods between 2002 and 2015.Declining pattern characteristics of metropolitan area density outward from city centers can be quantified by fitting the parameters to urban land density functions.An inverse S-shape function was identified as the best data fit.The four selected cities showed conventional density variation for decline in urban land area from city centers to outlying areas.Overall trend indicated that cities became more compact over time since the density differences between the urban core and urban fringe were greater with increasing infilling growth within the urban boundary.All four cities increased in size over time;however,the increasing amount of built-up land in the surrounding rural areas did not follow the same trend in each case.Some functional parameters required careful interpretation because of the linear shape of the city as in the case of Nakhon Phanom.Using highly detailed urban data resulted in lower densities of urban areas compared to the conventional pixel-based classification,and this affected the overall shape of the inverse S-shape function.The fitted parameters and their changing trends indicated that the urban land density function was useful for understanding urban form and urban sprawl in Thailand.Results can be used to develop a specific framework for other cities with similar attributes in the future.
文摘The present study analyzes the structure and dynamics of the forest landscape in a peri-urban area （Rome, Italy） during the city＇s expansion from 1949 to 2008 using landscape metrics and change detection anal- ysis of digital maps of the area （1500 km2）. While urban settlements increased continuously from 6.5 to 27.5 % of the study area, woodlands changed less clearly, with a moderate increase （from 11.2 to 11.9 % of the total area） and a higher fragmentation as a consequence of Rome＇s expansion. The structure of forest landscape changed along the urban-to-rural gradient with patch size increasing with the distance to the inner city in 1949 and substantial landscape homogeneity in 2008. The indicators proposed in this study inform dedicated measures for conserving forest and maintaining landscape diversity. Measures adopted in Rome＇s forestation plan to counteract woodlandfragmentation were analyzed and discussed. Based on the complex landscape dynamics found for Rome, an inte- grated multiscale planning approach targeting forest con- servation is considered a key contribution to urban sustainability.
基金supported by the National Natural Science Foundation of China (Nos. 41730647, 41801187, 32101325)Youth Innovation Promotion Association CAS (No. 2022195)
文摘The vertical distribution of air pollutants in urban street canyons is closely related to residents’health.However,the vertical air quality in urban street canyons has rarely been assessed using field observations obtained throughout the year.Therefore,this study investigated the seasonal and annual concentrations of particulate matter(PM2.5 and PM10),CO,NO_(2),SO_(2),O_(3),air quality index,and their responses to microclimatic factors at three height levels(1.5,27,and 69 m above street level)in an urban street canyon.The PM concentration was higher at 27 m than at 1.5 m in winter,whereas the situation was reversed in other seasons.It was found that photochemical pollutants such as NO_(2) and O_(3) were the primary pollutants in the urban street canyon.The days on which O3 was the primary pollutant at the height of 1.5 m accounted for 81.07% of the entire year.The days on which NO_(2) was the primary pollutant at the height of 27 and 69 m accounted for 82.49% and 72.33%of the entire year,respectively.Substantially higher concentrations of NO2 and O_(3) were found at the height of 27 m than at 69 m.In-canyon concentrations of NO_(2) and O_(3) were strongly correlated with air temperature,wind speed,and wind direction,which played important roles in photochemical reactions and pollutant dispersion.
文摘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.
