Urban Form Parameters Research Articles

The effect of urban form parameters on annual and diurnal cycles of land surface temperature with 30-meter hourly resolution

Understanding dynamic changes in urban land surface temperature (U-LST) is vital for improving urban thermal environment. Previous studies noted a close association between two/three-dimensional (2D/3D) urban form parameters (UFPs) and U-LST, but divergent conclusions emerged due to study scale and data spatiotemporal resolution. This study investigated the effect of 2D/3D UFPs on multi-temporal (hourly, diurnal, and annual) U-LSTs with 30-m spatial resolution, which is the first exploration of such dynamics at this fine scale. In addition, the influence of local climate zones (LCZs) was considered. Results showed that 2D/3D vegetation UFPs have the greatest summer cooling effect at 21:00, while 3D building UFP sky view factor (SVF) impacts minimum nighttime temperature more (5:00). The independently total explained variances (R2) of 2D UFPs (0.2–0.7) on seasonal average U-LSTs were higher than that of 3D UFPs (0.1–0.4) in most LCZs. LCZ 3 and LCZ 2 had the highest seasonal and daytime U-LST, respectively. Interestingly, SVF replaced normalized difference vegetation index as the dominant factor in LCZs 4–6 and LCZs A-C after summer. Findings of this study are useful for guiding urban planning, formulating urban heat island mitigation policies, and promoting sustainable development goals (SDGs 11, 13, 15) of cities and communities.

Energy Consumption and Outdoor Thermal Comfort Characteristics in High-Density Urban Areas Based on Local Climate Zone—A Case Study of Changsha, China

This study aims to investigate the characteristics of energy consumption and outdoor thermal comfort within the high-density urban fabric of Changsha. Two different types of building (residential and office), as well as three building forms (point, slab, and enclosed) were analyzed under the local climate zone scheme. Utilizing the ENVI-met 5.6.1 and EnergyPlus 23.2.0 software, simulations were conducted to assess the thermal comfort and energy consumption of 144 architectural models. Then, multiple regression and spatial regression were applied to predict the energy consumption characteristics of the study area. The results showed the following: (1) In the high-density urban area of Changsha, the central business district and historic old town adjacent to the Xiangjiang River are identified as areas with high energy use intensity. (2) Among the residential categories, the point-types LCZ-3 and LCZ-6, as well as the slab-type LCZ-4, exhibit the lowest energy use intensity. In contrast, the enclosed office buildings, LCZ-2 and LCZ-5, are characterized by the highest energy use intensity. (3) Urban form parameters such as floor area ratio and building shape coefficient have a significant impact on EUIwinter, while EUIsummer is highly related to the normalized difference vegetation index and building shape coefficient (BSC). (4) The slab-type LCZ-4 stands out with its notably lower cooling and heating energy use intensity, coupled with excellent thermal comfort, making it particularly well-suited for the climatic conditions of Changsha.

Urban morphology as a key parameter for mitigating urban heat? – A literature review

Abstract More frequent and intense heat waves, especially in urban centers, represent a growing challenge for urban designers and building planners. In the last five years, extensive research has been undertaken on the relation between urban form, including density, and urban heat phenomena. Dense urban configurations are often considered central drivers of hot microclimates. However, less dense cities easily cause other ecological (e.g. land consumption), functional (public mobility), and socioeconomic (social diversity) problems. Consequently, the current panoply of recommended heat mitigation and sustainability measures constitutes an unclear basis for strategic planning decisions. Thus, this study examines the literature on urban morphology in relation to urban heat events. Around 800 scientific articles and studies are categorized regarding the applied methodology, the studied geographic location, the observed urban form parameters, and the examined thermal parameter. Most identified literature uses traditional field measurement, remote sensing, numerical simulation, or a combination. Air temperature and land surface temperature are the most observed thermal parameters, while the growing number of studies that focus on human outdoor thermal comfort is highly relevant for effective heat mitigation and adaptation. This study suggests that from a scientific point of view, urban morphology measures do not principally carry a paramount role in heat mitigation compared to other aspects, such as vegetation or materialization. Current planning approaches for climate-resilient cities are highly case-specific, where no generally applicable rules or effective recipes regarding urban built form are available.

Breathing space in a compact city: Impacts of urban re-densification on Mumbai's low-income housing environment

Redevelopment of low-income settlements by re-densifying cities is a common approach in the Global South to improve living conditions and tackle the housing shortage. However, the effectiveness of the housing design in redevelopment schemes remains to be questioned. This study evaluates a proposed design of a slum redevelopment project in Mumbai, India, by comparing the environmental performance of three design schemes: the existing low-income housing, the redevelopment scheme proposed by the local government and a hypothetical design (modified scheme) that aligns with positive environmental outcomes identified in the current literature. The environmental factors such as the natural airflow, incident solar radiation and daylighting parameters were assessed by computational simulations and validated by a wind tunnel experiment. These factors were associated with direct and indirect density metrics of the three design schemes to inform better policymaking for slum redevelopment projects that seek to re-densify housing for the urban poor. The results indicated that the design performance of the redeveloped scheme is less preferable due to the unclean indoor air and inadequate daylighting conditions requiring large-scale demolition of the existing buildings. The modified plan requires minimal demolishment and demonstrates relatively better environmental performance. The study revealed that indirect density measures - building geometry factors and urban form parameters - are essential in affecting the ecological performance of housing. Considering these factors in design standards and policymaking for high-density redevelopment schemes can enable the “Goldilocks density” that significantly improves the quality of living while densifying the cities.

Tourism Morphometrics in Venice: Constructing a Tourism Services Index (TSI) to unmask the spatial interplay between tourism and urban form

Understanding how the built environment affects tourism saturation in cities is of central importance to the efficacy of tourism management strategies that rely on spatial datasets to inform space-specific policies. By employing the historic city of Venice (Italy) as a case study, this article provides a nuanced methodology defined as “tourism morphometrics” to inform tourism management plans and to detect urban form configurations prone to “overtourism.” The research contribution is twofold: first, it harnesses spatial datasets on lodging (6642 Airbnb listings, InsideAirbnb), dining (997 restaurants, Tripadvisor), and shopping (226 stores, Google Points of Interest) to construct a highly-granular ‘Tourism Services Index’ (TSI) that reveals the spatial distribution of tourism service capacity in Venice; second, it empirically reveals the spatial interplay between urban form parameters—landmarks, bridges, and street network—and TSI values. More specifically, statistical analyses found that TSI scores were positively associated with the number of street intersections, street widths values, and proximity to landmarks and bridges in Venice. The results offer insights into the relationship between tourism services and the spatial features of urban environments in which visitors move and behave. By leveraging by-product geospatial datasets, this research argues for a renewed management of overtourism through space-specific planning models.

Beyond costs: How urban form could limit the uptake of residential solar PV systems in low-income neighborhoods in Ghana

This paper examines the relationship between urban form, residential rooftop solar PV potential, and levelized cost of electricity (LCOE) in high-income, middle-class, and low-income neighborhoods in Accra, Ghana. Using building footprint data, ArcGIS Pro, and linear regression analysis, we find a statistically significant association between urban form parameters (building density, neighborhood compactness, building footprint area, suitable rooftop area, and near distance between buildings) and the rooftop solar PV potential in all the three types of neighborhoods. However, the well-planned high-income neighborhood exhibited the highest rooftop solar PV potential with low LCOE values for most houses, while the lowest rooftop PV potential and highest LCOE values were found in the largely unplanned low-income neighborhood. The low-income neighborhood exhibited higher density with clustered building patterns and, consequently, lower rooftop PV potential. The LCOE ranged between $0.02/kWh-$0.19/kWh for most buildings, with 92 %, 74 %, and 51 % of houses in the high-income, middle-class, and low-income neighborhoods falling within this range, respectively. We conclude that while capital subsidies for residential solar PV can boost their uptake by urbanites, their effectiveness could be limited in low-income neighborhoods due to the limitations imposed by their urban form. It may be more appropriate for policy interventions to target such neighborhoods with community solar schemes while targeting high-income neighborhoods with building integrated solar photovoltaics.

Investigating urban form, and walkability measures in the new developments. The case study of Garnizon in Gdansk

Sustainable transport choices are gaining much attention as they may support the global shift towards reducing the carbon footprint and developing more energy-efficient cities. The relation between urban form and sustainable transport has been discussed by academics and practitioners and there is a consensus that specific parameters of urban form can encourage walking and discourage car use. Following global recommendations on sustainable development, countries take steps towards strengthening pedestrian accessibility by implementing spatial characteristics of walkable neighbourhoods, but also by mobility and urban design strategies. This issue, however, is not properly recognised in countries with short experience in sustainable urban development, such as former socialist countries. In Poland no studies on walkability-related parameters of urban form have been carried out, hence the knowledge in this field is limited. This paper aims to address this gap by providing evidence of a newly built urban district located in Gdansk, Poland. We present the Polish case with three examples of new urban districts from Western Europe, that are designed as sustainable and walkable environments. The methodology is based on the descriptive case study. It includes characteristics of design parameters namely the components of the “walkability index” as well as mobility solutions and urban design guidelines. The results show the current position of Garnizon development in relation to the Western European cases with regard to the existing post-communist legacy and allow for indicating differences and possible shortcomings. Additionally, the study results can be discussed in the context of improving the quality of the housing environment in Poland through pedestrian-oriented development strategies.

Urban form simulation in 3D based on cellular automata and building objects generation

Modeling urban form change is fundamental to mitigate the negative impacts of urban development. Despite the extensive applications of cellular automata (CA) models in urban simulation, an important drawback of contemporary urban CA models is that they cannot explicitly represent urban form change in a 3D manner, hence hampering the proper evaluation of the impacts of urban form. This study addresses this issue by developing a hybrid approach of 3D urban form simulation. The proposed approach integrates a patch-based urban CA model and a tool for 3D modeling of building objects. A case study is carried out in Panyu, China, to evaluate the effectiveness of the proposed simulation approach. The experimental results show that the simulated urban land use pattern achieves an overall similarity of 83% as compared against the observed one. The building height predictions yielded by the random forest algorithm have relatively good performance, with the errors close to a standard floor height (3.18–4.57 m). Three scenarios of future urban form are simulated according to the narratives of the shared socioeconomic pathways (SSP). The SSP simulations are used to produce three sets of gridded morphological parameters that are compatible with mainstream regional climate models. The resulting urban form parameters are compared to infer the potential effects of different urban forms in the SSP scenarios.

Evaluating the Meteorological Effects on the Urban Form-Air Quality Relationship Using Mobile Monitoring.

Predictive models based on mobile measurements have been increasingly used to understand the spatiotemporal variations of intraurban air quality. However, the effects of meteorological factors, which significantly affect the dispersion of air pollution, on the urban-form-air-quality relationship have not been understood on a granular level. We attempt to fill this gap by developing predictive models of particulate matter (PM) in the Bronx (New York City) using meteorological and urban form parameters. The granular PM data was collected by mobile low-cost sensors as the ground truth. To evaluate the effects of meteorological factors, we compared the performance of models using the urban form within fixed and wind-sensitive buffers, respectively. We find better predictive power in the wind-sensitive group (R = 0.85) for NC10 (number concentration for particles with diameters of 1 μm-10 μm) than the control group (R = 0.01), and modest improvements for PM2.5 (R = 0.84 for the wind sensitive group, R = 0.77 for the control group), indicating that incorporating meteorological factors improved the predictive power of our models. We also found that urban form factors account for 62.95% of feature importance for NC10 and 14.90% for PM2.5 (9.99% and 4.91% for 3-D and 2-D urban form factors, respectively) in our Random Forest models. It suggests the importance of incorporating urban form factors, especially for the uncommonly used 3-D characteristics, in estimating intraurban PM. Our method can be applied in other cities to better capture the influence of urban context on PM levels.

The Relationship between Urban Density and Building Energy Consumption

Neighborhood characteristics influence natural urban energy fluxes and the choices made by urban actors. This article focuses on the impact of urban density as a neighborhood physical parameter on building energy consumption profiles for seven different metropolitan areas in the United States. Primarily, 30 × 30 m2 cells were classified into five categories of settlement density using the US Geological Survey’s National Land Cover Dataset (NLCD), the US Census, and Census Block data. In the next step, linear hierarchical spatial and non-spatial models were developed and applied to building energy data in those seven metropolitan areas to explore the links between urban density (and other urban form parameters) and energy performance, using both frequentist and Bayesian statistics. Our results indicate that urban density is correlated with energy-use intensity (EUI), but its impact is not similar across different metropolitan areas. The outcomes of our analysis further show that the distance from buildings within which the influence of urban form parameters on EUI is most significant varies by city and negatively changes with urban density. Although the relationship between urban density parameters and EUI varies across cities, tree-cover area, impervious area, and neighborhood building-covered area have a more consistent impact compared to building and housing density.

From urban form analysis to metrics for enhancing tsunami evacuation: Lessons from twelve Chilean cities

In the case of near-field tsunami emergencies, evacuation is considered the most important and effective method to save human lives. While significant efforts have been carried out to examine the relationships between urban forms and tsunami evacuation, challenges remain on delivering evidence-based urban design strategies, principles or metrics that could be applied by decision-makers to guide the physical development or retrofitting of tsunami-prone coastal communities around the world. In this paper, we propose a methodology that combines tsunami flood and evacuation modelling with statistical analysis, to examine the pedestrian evacuation potential of 67 urban samples extracted from 12 case studies in Chile. Our findings show that urban form parameters like the number of exit points out of an endangered area, the mean distance from the street network to these points, and the population density, can have a noticeable impact on tsunami evacuation times, which nonetheless is significantly dependent on the evacuees’ departure time. Moreover, we demonstrate that Chilean urban coastal development has been noticeably carried out through grid-like form patterns that might contribute to hinder evacuation in case of a tsunami emergency.

Impacts of urban form and urban heat island on the outdoor thermal comfort: a pilot study on Mashhad.

There is an increasing demand for cooling cities because of its importance on human health and the quality of life in outdoor urban spaces. However, the development of methods in improving outdoor thermal comfort and zoning cities based on outdoor thermal comfort is still challenging. In this work, we propose a new approach to cities zoning from the lens of outdoor thermal comfort in the arid climate of the city of Mashhad, Iran, and investigate the impacts of urban form characteristics on pedestrian thermal comfort. The effects of complex urban form parameters including height to width (H/W) ratio, canyon orientation, tree canopy cover, and building surface materials on the thermal comfort of pedestrians were studied in the arid climate of Mashhad. Microclimate simulation and analysis is conducted in ENVI-met software, and ArcMap is used to calculate Mashhad urban heat islands. Path analysis in SPSS presents an urban form formulation, which predicts approximate outdoor thermal comfort condition in current and future urban context of Mashhad and other cities with the same climate. We finally demonstrate the use of our research method as an alternative method for all cities: urban heat island (UHI) zoning can be used as a substitute for urban form zonings based on outdoor thermal comfort, especially in large cities where data collection on urban form can be difficult due to limited time and resources.

The Fractal Geometry of Turkey’s Urban Transportation Networks

This study presents a fractal analysis of the urban transportation systems of Turkey. Box-counting fractal dimensions were determined by using BENOIT, analysing the 81 cities in Turkey. A simple statistical model was derived, using log-linear functions, to indicate the relationships between fractal dimension and the urban form parameters of urbanized area, urban population, number of the urban transportation network’s lines, and the urban transportation network lines’ total lengths. The results show that the Turkish systems have box-counting fractal dimensions (Db) between 1.438 and 1.795. A strong correlation was found between Db and the Log of all urban parameters, with an R2 of 0.880. The strongest positive singular correlation, with R2 equalling 0.800, was between Db and the log of number of lines in network. Db and log of network line’s total length also had a strong positive correlation, with an R2 of 0.756. Moderate positive correlations were found between Db and the logs of both urbanized area and population, with R2 of 0.573 and 0.456, respectively. Results support the theory that considers fractal dimension an indicator of a network’s complexity, as a mature city would likely have a better, more complex transport network system than a less mature one.

The Influence of Diverse Building Height and Building Coverage Ratio on Outdoor Thermal Performance in Hot Climates: A Review

Although urban form can significantly affect outdoor climatic conditions, urban planners do not sufficiently consider such impact while designing new urban communities in Egypt. Proper configuration of urban blocks can make positive contribution to alleviating the adverse effects of urban climate. However, new cities are constructed to be formed from lowly dense buildings that overlook curvilinear streets networks without considering orientation. Furthermore, the use of unified building heights, spaces of low aspect ratio and high sky view factor lead to less shaded areas. The research at hand aims to shed light on literature that discuss urban form parameters and their relation with outdoor spaces thermal performance in warmer climates. These studies are classified, analysed and compared in terms of the investigated parameters, and the methodological approach of each study. The findings can help defining gaps in the existing literature while providing holistic overview of the current state of art.

DENSIDAD Y SUS EFECTOS EN LA TRANSFORMACIÓN ESPACIAL DE LA CIUDAD CONTEMPORÁNEA: CINCO TIPOLOGÍAS PARA INTERPRETAR LA DENSIFICACIÓN RESIDENCIAL INTENSIVA EN EL ÁREA METROPOLITANA DE SANTIAGO

Este trabajo busca caracterizar diversas expresiones del proceso de densificación residencial intensiva en el Área Metropolitana de Santiago (AMS), de manera de objetivar la discusión en torno al impacto de dicho proceso en el espacio urbano. La verticalización asociada a la densificación residencial intensiva transforma la morfología del tejido urbano, más precisamente, reconfigura la estructura de la manzana, esto es, la ordenación de lotes, circulaciones y edificios. Mientras la morfología urbana constituye un factor condicionante del proceso de densificación, el mismo proceso transforma el espacio urbano con distintos grados de incrementalidad, particulares manifestaciones espaciales y parámetros de desempeño de la forma urbana. Consecuentemente, la densificación residencial corresponde a un fenómeno que se extiende diferenciadamente en el AMS. Dado que la relación entre densidad y forma urbana es altamente compleja, para caracterizar la densificación residencial intensiva, la densidad se relaciona con otros parámetros de la forma urbana, tales como edificabilidad, ocupación de suelo y diversidad de usos.Este trabajo aborda la densificación residencial mediante el análisis y parametrización de la forma urbana de 16 fragmentos de 25 ha que evidencian procesos de densificación residencial a partir de 1990. Se proponen cinco tipologías de densificación, las cuales permiten avanzar hacia una mejor comprensión del fenómeno, y la interpretación de qué propiedades y variables espaciales las caracterizan: 1) hiperdensificación que reconfigura el tejido urbano tradicional; 2) densificación del tejido urbano pericentral con diversidad de usos, 3) densificación del tejido urbano pericentral residencial; 4) densificación con tendencia a la compacidad; y 5) densificación monofuncional de la manzana industrial.

Emergence of sub-optimal land utilization patterns in Indian cities

ABSTRACT This paper examines the urban morphology of Ahmedabad, a large and rapidly growing Indian city, to determine land utilization efficiency. It provides a nuanced understanding of land consumption patterns in public and private domains, and how sub-optimal land development patterns emerge. Urban form parameters analysed include public streets, building footprints, and public and private open spaces. The results show that land utilization is sub-optimal, with less land available under public domain and more land consumed as private open spaces (especially as margins and setbacks) leading to excessive fragmentation. Indian cities should rationalize their development regulations to improve land utilization outcomes.

Assessing cities: Applying GIS-based methods for mapping cross-scale spatial indicators

In recent years, several systems and tools to assess energy consumption and carbon emissions at scales beyond that of merely buildings, such as LEED, CASBEE and BREEAM communities have been development. However, reviews reveal a lack of robustness in these methods both in terms of an unstructured mix of qualitative and quantitative criteria and lack of focus on urban form parameters found to influence energy consumption and carbon emissions. A promising quantitative assessment system including various urban form indicators is developed by the Urban Morphology Institute (UMI) in Paris. Within the research centre on zero emission neighbourhoods in smart cities (ZEN), a GIS-based method is applied to analyze conditions of urban form known to contribute to carbon emissions. In this paper we demonstrate how a selection of the UMI indicators describing proximity can be further specified applying GIS-based methods. The potential of applicability of urban assessment system in planning as well as design processes will increase when linked to tools that are already implemented, and map visualizations as well as data provided by these methods are highly applicable in planning and urban design. As further research, methods described in recent research within ZEN and specified measures for calculating UMI indicators, will be tested in analyses of urban development areas in Norway.

Urban form and population density: Influences on Urban Heat Island intensities in Bogotá, Colombia

This paper presents a study based on the relationship between Urban Heat Islands (UHI) and population size (p) by considering the Population Density (PD) and the urban form parameters of different neighbourhoods in the city of Bogotá, Colombia. The aim is to understand the influence of the urban form, created by population concentration differences in the temperature of the city. For this purpose, every month throughout one year, air temperature data (obtained from nine different urban meteorological stations) were sampled and statistically treated to which population density could be respectively associated. The rural data were compared to the urban data to extract temperature differences (ΔTu-r). Moreover, different variables of the land cover and urban morphology were extracted and analysed in each neighbourhood around the stations. Among the meteorological stations, there was a significant and highly positive relationship among population density and thermal differences. In the same way, when finding which parameters of the urban form have a better relationship with PD and ΔTu-r, the Sky View Factor (SVF) and the Pervious Surface Fraction (PSF%) are highlighted. The results show that density above 14,500 inhabitants/km2 may cause air temperature differences higher than 1 °C, greater obstruction of the sky (SVF < 0.45) and a larger decrease in green areas and vegetation cover (PSF% <30). This paper concludes that urban form, expressed by land cover and urban morphology changes, caused by population density, has a great effect on temperature differences within the city of Bogotá.

Right-Sizing Cities for Maximum Power: Urban Form Parameters for New York City and the Greater Philadelphia Region

This paper examines the urban form parameters in theories and ideas related to the urbanizing world. Adopting emergy (spelled with an “m”) synthesis, we studied New York City and the Greater Philadelphia region to determine the appropriate urban form, including building height, development density, bulkiness, and transportation. The European and North American mid-rise urban block is an effective settlement type for reducing per capita emergy in construction and building operations. Buildings over 40 stories with a development density exceeding a floor area ratio of 5 tend to show higher emergy investments per person. Large and bulky buildings with low surface-area-to-volume ratios that reside on the periphery of cities consume a significant amount of energy due to conditioning building space and the increased transportation needs for commuters.

Mapping demand for residential building thermal energy services using airborne LiDAR

Within the urban environment the building sector typically accounts for around half of the total energy used, with the majority of this demand driven by thermal services including hot water and space conditioning. Accurately quantifying and locating building energy demand is essential to aiding energy management and planning initiatives across the city. However, a shortage of techniques that enable the effective scaling of individual building energy models to larger areas is evident. To help meet this need, we present a novel approach that utilizes airborne Light Detection and Ranging (LiDAR) data to populate a range of residential building energy and urban form parameters, including envelope resistivity, air leakage and solar gains. These parameters are then integrated with additional spatial datasets and allow for the calculation of baseline estimates of energy demand for contiguous regions within urban areas. We illustrate the outcomes of the model by predicting energy demand across a mixed residential neighbourhood in the City of Vancouver, Canada. Results indicate that the annual estimates of thermal energy demand closely match those derived from building energy simulation software (R2=0.93, p<0.001), while monthly estimates of demand show no statistically significant differences between our results and those from the simulation software (t=−0.11, p=0.91).