Type Of Urban Form Research Articles

Mechanisms of non-stationary influence of urban form on the diurnal thermal environment based on machine learning and MGWR analysis

The non-stationary impact of urban form at block scale on the diurnal thermal environment has not been extensively studied. To fill the gap, a comprehensive multi-scale research framework was constructed, integrating machine learning algorithms and multiscale geographically weighted regression (MGWR) analysis. The urban form types were extracted by machine learning algorithms from 2282 blocks of Dalian, a coastal city, and the contribution to the diurnal land surface temperature (LST) was evaluated. Based on MGWR, the non-stationary effects of urban form, human activity and spatial location on the diurnal LST were quantified, which indicated the contributing factors to the diurnal thermal differences among the form types. The result was as follows: 1) Blocks characterized by low vegetation and mid/low-rise buildings had the highest warming contribution for diurnal LST. 2) The impact of sky view factor (SVF) on diurnal temperature amplitude exhibited no significant spatial-temporal heterogeneity. 3) Building density had a prominent effect on diurnal temperature amplitude. 4) High-vegetation and open (SVF > 0.5) mid/mid-high/low-rise (15–50 m) buildings were recommended. This study provides a more precise basis for policymakers to develop climate adaptation strategies throughout day and night, particularly for coastal cities.

Developing a two-level machine-learning approach for classifying urban form for an East Asian mega-city

Having had the most rapid urbanization in the world since the 1990s, mega-cities in East Asia featured highly compact and atomized modernist architecture. With densely built modernist architecture and relatively free building regulations, it is challenging to trace the actual development of the whole city. Compared to European cities, their overall urban landscapes are much denser, higher, and functionally mixed. In order to achieve a quicker and more accurate identification of urban forms in mega-cities, this study proposed a two-level machine-learning approach. At the building level, we extracted features from topographic maps and building licenses to automatically classify building types. Four state-of-the-art multi-class classification models were compared. At the block level, we used building types as input data and compared two methods for block clustering. In total 61,426 buildings from Taipei were classified and grouped into 10 block types. Different from Western cities, many of the block types in Taipei were mixtures of different types of buildings. This approach is efficient in exploring new urban form types, especially for emerging mega-cities where block types are previously unknown. The result not only sheds light on the features of East Asian urban landscapes but also serves as important basis of type-based strategic plans for contemporary urban issues.

Climate action at the neighbourhood scale: Comparing municipal future scenarios

Municipalities face the direct impact of climate change events, but many are challenged to assess the potential outcomes of future climate action policies. It is essential for local municipalities to be able to evaluate cross-sector and cross-scale policy interventions, but many lack the expertise and resources for wholistic forecasting. This paper used a hybrid inter-scalar and interdisciplinary modeling approach to evaluate, compare, visualize, and reveal the performance of climate actions at building and neighbourhood scales of future ‘what-if’ scenarios for three neighbourhood urban form types (dispersed, corridor, nodal) in three cities in British Columbia, Canada (Vancouver, Victoria, Prince George). Results found that increases in population density combined with strict building standards and retrofitting older buildings decreased per person emissions per year by up to 84% by 2050. Within the neighbourhood-scale areas, building form and location had less impact. Population density and frequency of transit service were most important for mobility mode shifts. Concentrating density at transit nodes or along commercial corridors improved the percentages of residents within a five-minute walk of those services, but proximity to greenspaces showed mixed results. <em><strong>Policy relevance</strong></em> Municipal climate action policies cross sectors and scales. This analysis of future urban form and energy scenarios at neighbourhood scales reveals livability and greenhouse gas (GHG) outcomes. It provides evidence that compact neighbourhood form coupled with stringent building codes reduces GHG emissions. (1) Concentrating density at transit nodes or along commercial corridors improved the percentages of residents within a five-minute walk of those services, but proximity to greenspaces showed mixed results. (2) Within neighbourhood-scale areas urban form (building form and location) had less influence on shifting mobility modes than did overall population density and transit frequency. (3) British Columbia’s net-zero-ready building code, a performance-based code, resulted in notable energy-use reductions and related emissions reductions associated with the new building stock. (4) Retrofitting the existing building stock resulted in notable emissions reductions in the three neighbourhoods; however, for cities with growing high land value, the potential for sale and redevelopment is a disincentive to retrofitting.

Predicting housing construction period based on a cox proportional hazard model––an empirical study of housing completions in the greater Toronto and Hamilton area

The completion progress of residential development projects and the length of construction are frequently discussed in the construction industry, but rarely studied by urban modellers. Nonetheless, a realistic reflection of housing supply processes is important for urban microsimulation and land use modelling. To predict the dwelling units generated over space and time, this paper decomposes the housing supply process into two major components: housing starts and completions, the nature and modelling logic of which are quite different. This paper deals with the latter segment, aiming to answer the question of: how long will it take to complete construction of new dwellings? A Cox Proportional Hazard (CPH) Model is employed to examine the “survival” rate of residential building projects and the probabilistic distribution of construction periods. Narrowing down the scope of research, this study investigates housing completions at the individual project level, and discusses the impact of structure type, surrounding land use, and accessibility on the housing completion rate. The Cities of Toronto, Hamilton, and Brampton in the Greater Toronto and Hamilton Area (GTHA) were selected to conduct the empirical study, with each representing different types of urban form to test model compatibility. The hazard models show good performance in replicating completion rates, and the impact of each factor on hazard ratio indicates that, single detached dwelling units with relatively homogeneous land use have the shortest completion time. This study could provide one component of a comprehensive framework for modelling housing supply, especially in urban microsimulation systems.

Long-term changes in 3D urban form in four Spanish cities

Three-dimensional urban form has a considerable influence on urban sustainability, being the reason spatial planning regulate it. Yet, we know very little about the development of building density and building height over time. In this study, we characterize the horizontal and vertical patterns of urban development in Barcelona, Madrid, Valencia, and Zaragoza between 1965 and 2015. Our analysis is based on a unique combination of cadastral data and LiDAR point clouds, which we use to characterize building footprint, height, and volume, at decadal intervals. Subsequently, we characterize urban expansion and densification processes using building volume and Urban Form Types. We find that height of new buildings shows a significant downward trend during the 70′s for the four urban areas and a decreasing trend after the 2008 real estate bubble for the cases of Barcelona and Valencia. Over the analyzed period a decrease of 116, 313, 217 and 157 cm in average building height was observed for Barcelona, Madrid, Valencia, and Zaragoza, respectively. Urbanized volume of all cities together has expanded by roughly 350% between 1950 and 2015. Sparse built-up form showed the largest absolute increase, although it contains only a low fraction of new built-up volume. A clear trend towards expansion is observed in city outskirts and the development of new urban clusters in municipalities closer to the main city. At the same time, settlements have followed incremental steps towards densification of the city-cores over time. This study provides a first step towards comprehensive understanding of long-term changes in 3D urban form, which can inform the development of policies that target the third dimension in urban form to steer sustainable urban growth.

Urban Form and Function Optimization for Reducing Carbon Emissions Based on Crowd-Sourced Spatio-Temporal Data.

The low-carbon city has become an important global urban development-oriented goal. One important aspect of urban space is low-carbon urban planning, which has a vital role in urban carbon emissions. Which types of urban form and function allocations are conducive to reducing carbon emissions is therefore a key issue. In this study, the Futian and Luohu Districts of Shenzhen, Guangdong Province, China, are taken as an example to investigate this issue. Firstly, a “head/tail” breaks method based on the third fractal theory is adopted to obtain the minimum evaluation parcel of urban space. Then, the Landscape Shape Index (LSI), Fragmentation Index (C), Shannon’s Diversity Index (SHDI), and Density of Public Facilities (Den) are used to evaluate the form and function allocation of each parcel. In addition, the CO2 concentration distribution in this study area is acquired from remote sensing satellite data. Finally, the relationships between urban form, function allocation, and CO2 concentration are obtained. The results show that the lower the urban form index or the higher the urban function index, the less the CO2 concentration. To verify this conclusion, three experiments are designed and carried out. In experiment A, the CO2 concentration of the tested area is reduced by 14.31% by decreasing the LSI and C by 6.1% and 9.4%, respectively. In experiment B, the CO2 concentration is reduced by 15.15% by increasing the SHDI and Den by 16.3% and 12.1%, respectively. In experiment C, the CO2 concentration is reduced by 27.72% when the urban form and function are adjusted in the same was as in experiments A and B.

Combining environmental and social dimensions in the typomorphological study of urban resilience to heat stress

Over the past years, cities have become more prone to extreme and frequent heatwaves. In this regard, urban form plays an important role and several typomorphological classifications have been developed to describe the urban form characteristics that can exacerbate heat stress and influence people's health and comfort negatively (i.e. the environmental dimension of heat-stress resilience). Nevertheless, evidence from past heatwave disasters indicates that other urban form characteristics, not included in existing typomorphological classifications, can significantly affect heat-stress resilience by influencing the conditions of social interaction and the state of social ties and solidarities in urban neighborhoods (i.e. the social dimension). Therefore, this paper proposes a broader approach combining the aforementioned environmental and social dimensions in the classification of urban form types; and demonstrates its application in a real-world case by developing a data-driven typomorphological classification that complements existing ones with the missing social dimension. The results showed the possibility of numerically identifying neighborhood types that, through distinct urban form characteristics, have different potentials for enhancing the social dimension of heat-stress resilience. This has direct planning and design relevance as the quantifiable characteristics of these types can be translated into guidelines/rules and incorporated into local regulations/codes.

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

ABSTRACT 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 supervised urban form classification methods. The novelty of the proposed method is the Multiscale Residual Convolutional Autoencoder (MRCAE), which can learn the latent representation of different 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.

The Localization of &amp;#8220;Imported&amp;#8221; Urban Form in Northeast China: The Case Study on Circular&amp;#8211;Radial Space in Dalian City

After the “imported” urban forms, which originated from foreign cultures, were transplanted into Chinese cities, they generate brand-new urbanscape but suffer from a lack of cultural roots and a disconnection with the mainstream of contemporary urban planning. Thus, their current value and potential in urban renewal are questioned. The study takes the circular–radial space from the Baroque cities as an example to clarify the motivation of its import from the west to northeast China. It further clarifies their adaptive changes in form and function in the local urban context, through a case study on Dalian City. The study finds that different geometric patterns of existing circular–radial space were influenced by European, American, and Japanese urban planning theories to varying degrees, but with equal emphasis on symbolism and functionality. Their implementation in Dalian has a continuity in time and space. But due to the changes in topography, traffic, and planning concepts, their forms and functions tend to be independent, their connection weakens, and their importance recedes after the street network. The circular–radial space in Dalian led to distinctive urbanscape. But during their inheritance and transformation, the rationality of new forms and functions, as well as the necessity of continuing the initial ones need to be dialectically considered, so as to avoid dogmatic revival and antique reproduction. Finally, the study reconsiders the concept of “localization” of “imported” urban form, and constructs a general research pattern to provide a new perspective for understanding the transformation of similar types of urban forms.

Analysis of Relationship Between Urban Sprawl and its Driving Factors: A Case of Small and Medium Town in Sri Lanka

Measuring the level of urban sprawl is a challenging task that lacks a clear universal method. Therefore, it is worthwhile to investigate whether results differ with the methods utilized, to compute the level of urban sprawl. Consequently, this paper will also contribute to overcome the two limitations of emerging researches. Frist, Recent studies have utilized various methods to measure urban sprawl. However, the results of these studies were not compared and contrasted. Second, empirical studies have given less attention to identify the relationship between the level of urban sprawl and its driving factors such as urban form, urban landscape, population density, built-up density, accessibility, etc. Hence, this study supposes to quantify urban sprawl and identify the key factors influence on the level of urban sprawl. The study was conducted using the Expansion Intensity Index, Shannon’s Entropy value and Landscape Metrics. Ten small and medium towns were selected in the Sri Lankan context. The study able to demonstrate the influence of type of urban form, type of street pattern and changes in the accessibility of center compare to periphery area on the level of urban sprawl.

What evidence exists on the possible effects of urban forms on terrestrial biodiversity in western cities? A systematic map protocol

BackgroundAs urban areas expand, scientists now agree that the city is an important space for biodiversity conservation. Yet, still relatively little is known about how urban forms could have a differential impact on terrestrial species and ecosystems. If some reviews have been conducted to examine the link between biodiversity and urban characteristics at an infra-city scale, none have explored the relationship between urban organization and biodiversity and tried to assess the capacity of various urban forms to maintain and possibly favour flora and fauna in the city. The resulting map will present the state of knowledge regarding possible relationships between urban forms and its features on the establishment and settlement of terrestrial and temperate biodiversity at infra-city scale in western cities.MethodsThe systematic map will follow the Collaboration for Environmental Evidence (CEE) Guidelines. We will collect the relevant peer-reviewed and grey literature in French and English language. The scientific literature will be retrieved with the use of a search string in two publication databases, one environmental and one social science database (Web Of Science Core Collection, and Cairn.info). We will also perform supplementary searches (search engines, call for literature, search for relevant reviews). All references will be screened for relevance using a three-stage process, according to a predefined set of eligibility criteria. Our study will concentrate on urban areas at the infra-city scale in cities of the temperate biogeographical zone. The subject population will include terrestrial species and ecosystems, except for archaea and bacteria. The exposure will consider all types of urban forms described by any urban descriptors or measures including heterogeneity, fragmentation, housing density, organisation of urban matrix, urban fabric) and all types of urban features (e.g. size, age of the buildings, materials, urban artefacts). All relevant outcomes will be considered (e.g. species richness, abundance, behaviour). We will provide an open-access database of the studies included in the map. Our results will also be presented narratively, together with tables and graphs summarising the key information coded from the retained articles (e.g. study characteristics, types and areas of research that has been undertaken, types of exposure, population concerned, etc.).

Expanding in the mountains: spatial patterns of urban form in a rapidly urbanising small city of Vietnam

ABSTRACT Measuring urban form is particularly important in rapidly urbanising countries as it can help assess problems caused by inefficient planning. Despite this, there is a dearth of research on fine-scale measures of urban form in Asia and Vietnam. In this paper, we aim to identify spatial patterns of urban form measured at the intra-urban level in Lào Cai, a provincial capital city in northern Vietnam that has been transformed dramatically since its integration in the Greater Mekong Subregion. We compute 15 indicators of urban form divided into four groups: shapes of built areas, street connectivity, density of services and population, and accessibility. A spatial clustering of the indicators allows to identify five urban form types and their spatial patterns, showing that this small city is experiencing an extensive and fragmented urban growth. We question urbanisation policy underlying such urban form and suggest avenues for a more sustainable urban planning.

Design Strategies of Life Outside and Life Inside for Livable Multi-family Housing Environment

This paper discusses the issue related to social life within the context of a neighbourhood. It takes on the case study of multi-family housing, which its urban forms are generally monofunctional, stand-alone, large scale, spread out and car dependency. This type of urban form may cause inclusivity and isolation to its context and problems in social interactions within its neighbourhood. This study examined the concept of life outside and life inside in multi-family housing design to create a more livable housing environment. The life outside concept aims to create a human-oriented neighbourhood by directing daily human activity towards outdoor space, through the integration of proximity, density, dan diversity. While the life inside concept aims to allow, residents to socialize with others through the design of a high probability of encounter zones in the building. Based on the observation at a multifamily housing complex at Rainbow Springs, Tangerang, this study proposed design criteria and strategies for a livable multi-family housing environment within the neighbourhood and inside the building itself. This study implies that integration between site planning and building design should be taken into consideration to form a livable neighbourhood.

An Investigation of the Quantitative Correlation between Urban Spatial Morphology Indicators and Block Wind Environment

The research purpose of this work is guiding the spatial morphological design of blocks via relevant indicators to realize suitable wind environments. In doing so, it is necessary to find the most suitable indicator types and value ranges for each urban spatial morphology. At present, most of the relevant research has been based on the numerical simulation of ideal block shapes and rarely proposes results based on actual block types, which often tend to be complex environments. Therefore, this paper firstly presents a theoretical speculation on the main factors influencing indicator effectiveness via analyzing physical significance and formulating principles for each indicator. These speculations are verified via wind environment measurement and statistical analysis, indicating that porosity (P0) can be used as an important indicator to guide the design of block wind environments in the case of deep street canyons, while frontal area density (λF) can be used as a supplement in shallow street canyons with no height differences. Finally, computational fluid dynamics (CFD) is used to quantify the impact of block height difference and street canyon depth on λF and P0, thereby finding suitable types of urban form and value ranges for λF and P0. This paper provides a feasible wind environment index system for urban designers.

Trade-Off Relationship of Arable and Ecological Land in Urban Growth When Altering Urban Form: A Case Study of Shenzhen, China

Over the last few decades, rapid urban expansion has spread over a great deal of arable and ecological land, leading to severe social and environmental issues. Although different urban growth scenarios cause varying types of urban forms to emerge, there is currently a lack of empirical studies and other research on these different forms. Therefore, it is important for decision-makers to have an improved understanding of the relationships between arable land and ecological land under different urban form conditions in order to implement sustainable urban development policies. This study utilized a patch-based, multilevel stochastic urban growth model to simulate Shenzhen’s urban growth until 2035. To determine the impacts of urban forms and population density on land use, we established five scenarios to simulate urban expansion and land-use changes at the sub-regional scale. The results revealed the trade-off relationships that emerge when altering the urban forms or population density, which shows that no single policy can conserve arable land and ecological land simultaneously. The results also revealed that sub-regions have distinct responses to alternative urban form scenarios compared with an entire region. Decision-makers and planners should consider the urban form in order to optimize development projects that fit local conditions and achieve more sustainable development.

The global homogenization of urban form. An assessment of 194 cities across time

The spatial structure of cities, i.e. their composition, shape and degree of fragmentation or compactness, is a physical expression reflecting development efficiency. Identifying the evolution of urban systems in time and space is crucial towards sustainable urban development. In this paper, we assess the spatial structure of 194 cities from 1990 and 2015, in order to identify patterns, clusters of similar cities, trajectories, and the global distribution of urban form. We delineated the contiguous urban fabric, employed landscape metrics to quantitatively describe urban patterns, applied a Principal Component Analysis (PCA) to reduce the dimension of data to an uncorrelated set of variables and identified groups of cities with similar urban forms by means of hierarchical clustering. We found four types of urban form: compact-grey, transitional, ragged-small and fragmented-complex cities. Globally, continentally and regionally, cities have followed a trend towards more homogeneous urban forms, most of them becoming transitional as a consequence of both, processes of fragmentation and compactness. The only exception of this trend is a group of large cities in Australia, New Zealand and the United States, which are still predominantly fragmented-complex. Under the persisting process of urban expansion, small to medium-sized cities showed to be the most dynamic in terms of expansion and change in urban form, which makes them key towards sustainable urban development. This analysis contributes to the understanding of the transformations induced by the process of urban expansion that shapes urban form. Such information is crucial for achieving urban sustainability.

Built environment, urban vitality and social cohesion: Do vibrant neighborhoods foster strong communities?

Urban vitality and social cohesion both provide multiple benefits in cities. While it has been argued that urban vitality – the liveliness of cities – may strengthen social cohesion, this has not been sufficiently examined by empirical research. This paper presents and tests a model in which urban vitality mediates the relationship between built environment characteristics and neighborhood social cohesion, using survey and geospatial data from the Oslo metropolitan area. We find that neighborhood density and land use mix are positive predictors of urban vitality, but are negatively associated with social cohesion. Green space is found to be associated with lower urban vitality, while public transport accessibility is associated with higher social cohesion. Results indicate seemingly contradictory relationships between the built environment, urban vitality and social cohesion. On the one hand, although compact urban form has higher levels of urban vitality, it has lower levels of social cohesion compared to low-density, single-use urban form. On the other hand, for similar urban form types, urban vitality is found to be positively associated with social cohesion, suggesting that local initiatives and interventions aiming to increase residents’ walking and social activity within their neighborhood could also strengthen social cohesion.

Impacts of multi-scale urban form on PM2.5 concentrations using continuous surface estimates with high-resolution in U.S. metropolitan areas

This study explores the relationship between urban form at the metropolitan and neighborhood scale and fine particulate matter (PM2.5) concentrations by establishing multi-level regression models. This study has different assumptions about urban form depending on the scale used. While at the metropolitan scale, the urban form is related to the change in travel behavior, at the neighborhood scale, it is related to proximate emission sources such as roads, emissions facilities, employment centers, etc. The study shows that at the metropolitan scale, higher urban fragments, population density, and road density are associated with higher PM2.5 concentrations; higher job-resident balance and accessibility to schools are associated with lower PM2.5. At the neighborhood scale, a higher density of the nearby emission sources and higher accessibility to destinations are associated with higher PM2.5 concentrations. Urban fragments and land use mix have consistent impacts on air quality compared to preexisting studies. While population density and road density have two conflicting assumptions regarding PM2.5, in this study, the net effect of population density and road density on air quality is negative. Accessibility to destinations has different associations with PM2.5 depending on the scale of urban form measurement. At the metropolitan scale, high accessibility to destinations lessens PM2.5 concentrations by reducing vehicle distance. On the other hand, at the neighborhood scale, high accessibility to destinations makes it close to areas, which concentrate air emissions. We suggest that urban planners and decision-makers establish different strategies depending on urban form types when there are urban development plans.

Urban kampung and household energy consumption in Bandung, Indonesia

This paper aims to understand the energy consumption of a type of urban form known as urban kampung in Bandung, Indonesia. The high building density characteristic of urban kampung often considered as a more energy efficient urban form. This paper tries to explore it by comparing the energy consumption and behaviour of people living in urban kampung with the energy consumed by those who live in organised settlements in form of vertical housing/flats (rumah susun). A questionnaire survey was conducted to 200 households living in the three neighbourhoods in Bandung, which represented the two types of urban form. The preliminary result shows that the energy consumption of urban kampung is slightly lower but somewhat similar compared with the vertical housing. The parcel size are probably the factor that affected this result, since the other components such as electricity bill, cooking fuel, and transportation expenditure do not express any differece within the two types of urban form. This study provides insight for policy-maker and city planners on the benefit of urban kampung to achieve a more energy efficient city. The city government might consider the strategy of revitalising and improving the urban kampung before converting them into vertical housing.

Urban form, travel behavior, and travel satisfaction

The relationship between the built environment and travel satisfaction has not been adequately explored in previous research. This study examines how urban form affects travel satisfaction using survey and interview data from Oslo metropolitan area, which is a good case for such a study since compact and sprawled urban forms are found to a large extent in the same city region. Results suggest that commute satisfaction as well as leisure travel satisfaction are significantly higher for residents of compact urban neighborhoods than those of sprawled suburbs. The article further focuses on commute satisfaction and finds that this difference is mainly due to differences in (a) trip duration and (b) travel modal split between the two urban form types. (a) Shorter distances to the city center and higher neighborhood densities are associated with significantly lower trip duration to work or education. This lower trip duration experienced by compact-city residents significantly contributes to their higher travel satisfaction. (b) Significant differences in the impact of travel mode on travel satisfaction, controlling for trip duration, are found. From most to least pleasant, travel modes are evaluated as follows: (1) walk, (2) bike and train, (3) bus, tram and metro, and (4) car. These differences contribute to the higher travel satisfaction found in compact neighborhoods, since residents of compact neighborhoods use active travel modes (walking and cycling) to a high extent and the car to a low extent, while suburban residents walk and cycle significantly less and use the car significantly more. Overall, the findings of this study suggest that compact-city policies and car restrictions that are currently applied or planned to be applied in several cities worldwide can have a positive impact on travel satisfaction as they lead to shorter trip durations and more active travel compared with urban sprawl policies.