Urban Density Research Articles

Addressing Urban Sprawl: is Densification the Solution? A Case Study of Sétif, Algeria

Objectives: The rapid and uncontrolled urban growth in Sétif, northeastern Algeria, has resulted in horizontal densification, continual expansion, and the conversion of agricultural land into urban areas. This transformation highlights the need for effective territorial strategies to manage urban growth sustainably. The primary objective of this study is to promote urban densification through concepts like "inward urbanisation" and "building the city within the city," aiming to optimise land use and counter the negative impacts of urban sprawl. Methods: To address the challenges of urban sprawl and its environmental impacts, the study employs a morphological approach. A Geographic Information System (GIS) is utilised in conjunction with data from the General Census of Population and Housing (RGPH) to analyse spatiotemporal changes in Sétif. This methodological approach enables a detailed examination of the city's morphological and demographic evolution, providing insights into patterns of urban expansion and densification. Results: The findings reveal various strategies for urban development in Sétif, focusing on alternatives to traditional urban density and sprawl. The study identifies and suggests the implementation of new, dense, and hybrid urban forms that align with sustainable development goals. These urban forms are designed to enhance the city’s livability while respecting societal needs and environmental considerations. The strategies proposed address the necessity for adaptable urban designs that support a more compact, resource-efficient city model. Conclusion: This research underscores the importance of rethinking urban planning strategies to manage rapid urbanisation in Sétif. The proposed strategies are essential for transforming Sétif into a dense, sustainable, and appealing urban environment. The study advocates for a shift from expansive urban growth to a densification model that promotes sustainability and aligns with the evolving expectations of the city’s residents.

Greening urban areas in line with population density and ecological zone can reduce premature mortality

Urban green space and urban compactness are each important principles for designing healthy, climate-resilient cities. The principles can co-exist, but greening may come at density’s expense if not considered deliberately. Existing studies estimating health impacts of greening scenarios have not considered what level of greenness is attainable for different population densities. Here, using the square kilometer as the unit of analysis, we estimate non-accidental mortality that could be prevented among adults older than 30 by greening that small area to a level of greenness assumed to be attainable based on its broader urban area (N = 15,917 globally), population density, and ecological zone. Results suggest a large potential for urban greening even in the most population-dense parts of cities such that on average 54 deaths per 100,000 could be prevented per year in those areas. That estimate may be about 25% higher or lower due to uncertainty in the underlying model.

Evaluating the Environmental Kuznets Curve: The Role of Renewable Energy, Economic Growth, Urban Density and Trade Openness on CO2 Emissions. An Analysis for High-Income Countries Using the CS-ARDL Model

Evaluating the Environmental Kuznets Curve: The Role of Renewable Energy, Economic Growth, Urban Density and Trade Openness on CO2 Emissions. An Analysis for High-Income Countries Using the CS-ARDL Model

Spatial suitability of urban land use models for poverty alleviation in the cities of Nigeria

Many models depicting the spatial dimensions of poverty are based on cities in developed countries, raising questions about their appropriateness for urban spaces in developing countries. This study evaluates the spatial suitability of these models in understanding poverty distribution and informing alleviation efforts related to Sustainable Development Goal (SDG). One in cities of developing nations. A grid sampling technique in ArcGIS 10.8 was used to select 1098 households across 56 wards in three mid-sized Nigerian cities. Household data were collected through structured questionnaires using GeoODK, and Maxar high-resolution imagery was used to assess urban building density. The Foster-Greer-Thorbecke (FGT) poverty indices and Pearson correlation were applied for analysis. Results showed that over 29 wards had a poverty incidence and gap index greater than 0.20, while poverty severity remained below 0.20 in most wards. High building density was more prevalent in the city’s interior. Significant correlations were found between the income poverty gap (p = 0.005, r = 0.367), poverty severity (p = 0.009, r = 0.346), and building density. The study concludes that these models are suitable for informing poverty alleviation policies in mid-sized cities of developing countries, especially Nigeria.

‘They’re not dog friendly because they’re not anyone friendly’: living with dogs in two densifying London neighbourhoods

Since the late 1990s, policy makers in the UK have promoted building higher density housing. Notably absent from this policy are the companion animals with whom we share our homes and public spaces. Their absence is all the more surprising given that dog companionship is often associated with the same outcomes as championed by the density and compact city agendas—social cohesion, community well-being, and active lifestyles. Based on research conducted in two London neighbourhoods, this paper explores how people experience urban density when with a dog, the challenges and opportunities they encounter, and how they negotiate their way through an often confusing and unspoken web of rules, laws and norms. The research builds on work which examines human-dog relations, arguing that the lack of clarity around where dogs are and are not welcome is reflective of the ways dogs are ambiguously positioned in relation to discourses of density and urban living. The ways urbanism is promoted in the UK is not politically neutral, nor are the ways some dogs are included or excluded from this imagining. We argue that the absence of clarity about dogs is constitutive of shifting and often confusing discourses about animals, urbanism, and densification.

Urban Renovation from Precarious to Sustainable Districts: Study Case of Mvog-Ada in Yaounde

This article explores the possibility of transforming precarious neighbourhoods, commonly known as slums, into good-living and environmentally- friendly places by rethinking their layout. It examines the state of the study case and highlights the relationships between the road system, parcels of land and other components of the urban fabric, with the aim of resolving the problems caused by the poor occupation of urban space and the lack of architectural knowledges and basic infrastructure necessary for people's lives in Cameroon. This research addresses the problems of anarchic urbanisation, urban densification and unhealthy living conditions, it proposes concrete solutions for decongesting the area, strategically redeveloping the space and ensuring the sustainable development of the site, while incorporating a biomimetic and circular approach. To achieve this goal, it was important to put in place a renovation strategy that is both up-to-date and adapted to the local context. With this in mind, this work presents a comprehensive and innovative master plan designed to solve the problems of development, bad urban traffic and degradation of the area through the use of an appropriate methodology of sustainable urban planning. Finally, the concept of sustainable district is presented as a pillar of the development of precarious districts and as an opportunity of growth for the development of their country.

INTEGRATING SOCIO-ECOLOGICAL CONNECTIONS INTO URBAN PLANNING

Urban ecology increasingly recognizes urban vacant lots as spaces with untapped aesthetic, social, and environmental potentials. This study focuses on strategies for converting these lots into green areas in Mossoró, a semi-arid city in Brazil, by analyzing urban connectivity patterns. Using a Geographic Information System, the study identifies priority areas for green space conversion based on factors like urban planning, density, land cover, and vacant lots. The analysis revealed 429 hectares of highly suitable land for conversion. A resistance surface was also created, factoring in public amenities and urban infrastructure, which showed varying levels of resistance to human movement. Areas with well-developed infrastructure had lower resistance, encouraging human and ecological movement. Connectivity modeling highlighted a need for more green infrastructure, especially in peripheral regions, to address socio-spatial fragmentation and enhance urban resilience in Mossoró. Keywords: Connectivity, Green Infrastructure, Urban Vacant Lots.

Distribution Patterns of Urban Spontaneous Vegetation Diversity and Their Response to Habitat Heterogeneity: A Case Study of Five Cities in Heilongjiang Province, China

Spontaneous vegetation is an important component of urban biodiversity and an excellent agent for exploring the mutual feedback mechanism between urbanization and urban ecosystems. Rapid urbanization has had a significant impact on the composition, structure, and distribution patterns of urban spontaneous vegetation diversity. Studying the diversity distribution patterns and causes of urban plant communities is beneficial for understanding the formation and maintenance mechanisms of plant diversity in specific urban habitats. This study selected five cities in different climate subregions of Heilongjiang Province as research targets and conducted field research using uniform sampling and typical sampling methods. The composition, distribution pattern, and driving factors of spontaneous vegetation were analyzed. The results showed the following: (1) A total of 633 examples of spontaneous vegetation were recorded, belonging to 93 families and 341 genera, mainly consisting of herbaceous plants and native plants. (2) The diversity index and similarity index of spontaneous vegetation in gravel-type abandoned land habitats are higher than those in other habitat types, while the diversity index of spontaneous vegetation in trees and shrubs is lower, and there is no significant difference in regards to different habitats. (3) Urban population density is a key factor affecting the diversity of native plants, while woody plant coverage, patch area, and landscape trait index are key factors affecting non-native plants. (4) The results of canonical correspondence analysis (CCA) showed that the total explanatory power of environmental characteristic factors in regards to the distribution pattern of spontaneous vegetation was 7.5%. The closest distance between adjacent patches, the coverage of woody plants in patches, the distance from the city edge, the patch area, and the surface impermeability of the buffer zones were key factors affecting the distribution of dominant species in spontaneous vegetation communities. The research results will provide an important reference for the conservation of urban biodiversity and the construction of low-maintenance urban green space plant landscapes in Heilongjiang Province.

From urban clusters to megaregions: mapping Australia’s evolving urban regions

This study employs percolation theory to investigate the hierarchical organisation of Australian urban centres through the connectivity of their road networks. The analysis demonstrates how discrete urban clusters have developed into integrated regional entities, delineating the pivotal distance thresholds that regulate these urban transitions. The study reveals the interconnections between disparate urban clusters, shaped by their functional differentiation and historical development. Furthermore, the study identifies a dichotomy of urban agglomeration forces and a persistent spatial disconnection between Australia’s wider urban landscape. This highlights the interplay between urban densification and peripheral growth. It suggests the need for new thinking on potential integrated governance structures that bridge urban development with broader social and economic policies across regional and national scales. Additionally, the study emphasises the growing importance of national coordination in Australian urban development planning to ensure regional consistency, equity, and productivity.

Examining the Causal and Heterogeneous Influence of Three-Dimensional Urban Forms on CO2 Emissions in 285 Chinese Cities

Despite the efforts to examine the influence of urban forms on CO2 emissions, most studies have mainly measured urban forms from a two-dimensional perspective, with relatively little attention given to three-dimensional urban forms and their causal relationships. Utilizing the built-up area dataset from the Global Human Settlement Layer (GHSL) project and the carbon emission dataset from the China City Greenhouse Gas Working Group (CCG), we examine a causal and heterogeneous effect of three-dimensional urban forms on CO2 emissions—specifically urban height, density, and intensity—in 285 Chinese cities. The empirical results reveal a robust and positive causal effect of 3D urban forms on carbon emissions. Even when incorporating the spatial spillover effect, the positive effect of 3D urban forms remains. Moreover, GDP per capita and total population have a greater impact on urban CO2 emissions. Additionally, we find that the influence of 3D urban forms on CO2 emissions is U-shaped, with total population serving as a moderating factor in this effect. Importantly, there is significant geographic and sectoral heterogeneity in the influence of 3D urban forms on CO2 emissions. Specifically, the influence of 3D urban forms is greater in eastern cities than in non-eastern cities. Furthermore, 3D urban forms primarily influence household carbon emissions rather than industrial and transportation carbon emissions. Therefore, in response to the growing challenges of global climate change and environmental issues, urban governments should adopt various strategies to develop more rational three-dimensional urban forms to reduce CO2 emissions.

Examining the relationship between the built environment and carbon emissions from operating vehicles: enlightenment from nonlinear models.

Carbon emissions from urban transportation significantly contribute to overall transportation emissions and are a major cause of the continuous rise in global temperatures. Understanding the spatial distribution and influencing factors of carbon emissions from operating vehicles can aid in formulating targeted policies and promoting emission reduction. To analyze the factors influencing urban traffic carbon emissions, we calculated emissions using trajectory data from operating vehicles in Shenzhen. We then used gradient boosting regression tree methods, specifically RF, XGBoost, and LightGBM models, to analyze the impact of the built environment on vehicle emissions. We used the XGBoost model for detailed factor analysis by comparing the models. The results indicate that bus stops, intersections, housing density, metro stops, and land use mix are the top five factors influencing emissions. When road density is 0-15 km/km2, the distance from the city center is 0-6 km, and the population exceeds 2000/km2, the built environment significantly reduces vehicle emissions.

Mapping municipal land policies: applications of flexible zoning for densification

Municipalities develop individual land policies and can choose not to apply available planning instruments or to apply them differently than intended. While this strategic action can endanger the effectiveness of public policies, it is rarely considered in large-scale analyses. A new geospatial method is presented that captures such strategic action. Empirical evidence from the Canton of Bern, Switzerland, reveals municipalities’ application of planned unit development (PUD), an instrument potentially allowing for flexible zoning negotiations to promote densification. Detailed zoning and building data from the period 2002–23 are used to examine the variation in PUD application by municipalities and whether they apply it to enable densification. Distinguishing by municipality type (i.e. urban core, small town, suburban, rural or touristic) reveals that PUD application is connected to projects with higher building density, more complex parcel changes and, for urban and suburban municipalities, higher density gains in low-density neighbourhoods. However, rural municipalities seldom apply PUD. New indicators of planning complexity provide an insight into whether municipalities apply instruments to enable densification under difficult circumstances. Practice relevance Many policy instruments are provided for in the law, but it is unclear whether and how they are used in practice by municipalities. Following urban densification objectives, municipalities often struggle to implement planning or housing policy instruments, which target private landowners and developers. Therefore, evaluating how different municipalities apply policy instruments and how this application contributes to reaching stated policy goals is crucial. Therefore, this research explores new ways to capture the effect of policy instruments with spatial analysis. Furthermore, by examining the real-world implementation of PUDs, this research sheds light on possible barriers to PUD application for densification, thereby helping policymakers and urban planners improve the effectiveness of public policies.

A micro-scale look into pedestrian thermophysiological comfort in an urban environment

Different spatial scales enable the analysis of thermophysiological conditions of pedestrians in an urban environment. A higher resolution hotspot analysis was conceived using GIS technology in some areas of Lisbon with different morphological conditions. Eleven hotspots were found across six study areas, located in high to moderate urban density conditions and in different types of urban spaces. So, six hotspots were found in avenues (high urban density conditions), three in streets, and two in general open spaces (moderate urban density conditions). These spaces are characterized by being busy areas with high anthropogenic influence, with high-absorbing and reflective materials, and with very poor green infrastructure. Environmental conditions, namely, radiation, mean radiant temperature, and air temperature, were the main cause of hotspot existence, and the main propellers for UTCI intensification. The urban density variable was also found to be important, especially in avenues and open spaces. In these areas, the adjusted component for environmental and urban density conditions can increase 0.60 to 1.35 °C in open spaces and 0.30 to 0.60 °C in avenues, each time there is a one-unit increase in the component. Trees, either in the street or in parks, have generally been found to decrease the UTCI.

Thermal preference and pleasantness of a students’ population in a coastal urban area during summer

In thermal comfort research, two main domains are identified: objective and subjective. This study focusses on the latter, examining various aspects of preference, sensation, and pleasantness. It also clearly distinguishes each concept and sets the groundwork for their standardised use in urban planning and urban climate studies. Additionally, this study emphasises the often-overlooked geographical perspective, aiming to address previous gaps in this research area. Environmental conditions were found to be the main determinants influencing pedestrians' thermal sensation, preference, and pleasure. Key factors include air temperature, solar radiation, and wind speed, which exhibit strong correlations with pleasure responses. Additionally, urban density, clothing type and colour, shading, sex, and weather type significantly impact thermal sensation and reported pleasantness. It was observed that people who overdressed for the season, wore dark or warmer clothes, experienced air temperature and solar radiation more intensely. Similarly, those in high-density urban areas, without shade, or when weak continental wind conditions were observed, reported stronger thermal sensations. Women generally sensed air temperature and solar radiation as more intense compared to men. These factors influence thermal pleasantness, varying in importance, spatial distribution, and statistical relationship. Higher wind speeds, particularly from an Atlantic direction, were found to enhance thermal pleasantness by balancing conditions and reducing thermal sensation votes for air temperature and solar radiation. Green areas also increased thermal pleasantness by lowering air temperature and solar radiation sensations and promoting a sense of happiness among pedestrians.

Barn owl site occupancy and breeding success in relation to land use and nest box characteristics

AbstractAgricultural landscapes play a crucial role in enhancing biodiversity because of their widespread presence over the Earth and their ability to encompass diverse ecosystems. Recognizing this, numerous governments are incentivizing farmers through direct payments to adopt sustainable practices, such as managing extensive pastures and meadows, planting wildflowers, or establishing hedgerows. However, the benefit of such sustainable practices on vertebrate species is not well understood. From 2018 to 2020, we investigated nest occupancy, fledging success, and clutch size of a Swiss population of barn owls (Tyto alba) with respect to nest box characteristics and the presence of extensive agriculture and urbanization in areas surrounding nest boxes. Our results revealed that extensively used pastures were positively associated with site occupancy but negatively associated with clutch size. The proportion of urban areas was negatively related to both site occupancy and clutch size. The altitude of the nest box location was negatively correlated with occupancy, and the number of nest boxes placed at the same site (either 1 or 2) was positively correlated with site occupancy. Moreover, clutch size, but not fledging success, was larger in nest boxes placed outside barns than in nest boxes placed inside barns. Based on these findings, we recommend installing nest boxes at locations <700 m in altitude and in pairs on the same barn, incorporating biodiversity promotion areas into agricultural landscapes, and avoiding dense urban areas in favor of rural zones with lower urban density. Understanding the nuanced relationships between nest box characteristics, environmental factors, and breeding success provides valuable insights for optimizing artificial nesting sites and enhancing the overall reproductive success of barn owls.

Urban density and spatial carbon emission performance of megacities in China

Increasing urban density promotes a greater social role for cities. The current low-carbon city development goals put forward higher requirements for carbon performance. Based on the viewpoint of minimizing natural resource input and maximizing value acquisition in ecological benefits, the influence of urban density on spatial carbon performance is analyzed by polynomial function relationship, and Beijing and Shanghai with different urban function positioning are taken as examples for comparative analysis. Combined with Point-of-Interest (POI), the classification benchmark of industrial activities was established, and the spatial kernel density of ArcGIS software was used to analyze the industrial agglomeration characteristics of the two cities. The results show that: 1) The “increase-decrease-increase-decrease” trend of urban spatial carbon performance over time fluctuates around the unary linear trend of urban density.2) Population and building density are too low or too high, which is not conducive to emission reduction. The change of economic density is influenced by the industrial structure. The change of urban density is negatively correlated with the growth rate of spatial carbon performance. In a certain development stage, the increase of urban density will inhibit the growth of spatial carbon performance to some extent. 3) Maintaining the original economic and industrial structure, the increase in economic density brought by the simple expansion of scale is not conducive to emission reduction. The increase of economic density brought by the transformation of economic or industrial structure and the reduction of the proportion of secondary industry is conducive to urban emission reduction.

Strategic easing of height restrictions: Unveiling the intersection of free market principles and colonial mentality in Hong Kong’s urban densification

ABSTRACT High-density housing development is considered a pragmatic response to the conflicts between land scarcity and population growth. Under the rhetoric of (neo)liberalism, the flourishing private housing market narrative was anchored throughout the last century, along with significant contributions from government regulations. The 1955 Buildings Ordinance, which eased height limits, laid the groundwork for Hong Kong’s high-density foundations. The existing historiographical literature examines this from a technical perspective. However, it overlooks the decision-making processes behind these regulations and their alignment with or deviation from free market principles. This study examines colonial archives to scrutinize the colonial government’s approach to building regulations, revealing that easing height restrictions was not merely a technical adjustment but a calculated response to broader economic and demographic challenges. It was a strategy to stimulate private housing development and manage population growth without significantly increasing government spending. This raises concerns regarding prevailing assumptions that the colonial government supported a free-market approach to housing rather than exploring the debates and deliberations that shaped these policies. By comparing colonial experiences in Hong Kong and London, historical analysis challenges the conventional understanding of Hong Kong’s urban development, thereby highlighting the contentious relationship between liberal economic policies and the colonial administrative framework.

No Report, No Densification? A Spatiotemporal Analysis of Urban Densification and Reporting Practices in World Heritage Properties

As urbanization accelerates, World Heritage properties, critical conservation areas, face a growing threat of urban densification, jeopardizing their Outstanding Universal Value (OUV). States Parties, the countries that have ratified the World Heritage Convention, are responsible for submitting periodic reports on the state-of-conservation of their World Heritage properties. These reports should explicitly address any instances of urban densification that may be occurring. But do they? This research investigates the relationship between urban densification and reporting practices in World Heritage properties over time and space. Through a spatiotemporal analysis, by analyzing changes in the built-up area within the core zones of cultural World Heritage properties from 1985 to 2015. We found that urban development, including housing, infrastructure, and tourism facilities, has significantly impacted World Heritage properties and an increase in built-up area can be observed especially in properties not reporting on urban threats.

Influence of Solar Radiation on Microbiological Degradation of Sewage Submarine Outfalls and the Safety of Bathing Areas

The ocean disposal of wastewater is an efficient alternative in the sewage system of coastal areas since the urban density of such regions is a barrier to the settlement of conventional sewage treatment plants. In addition, the associated costs of this alternative are significantly lower than the convention in the long term. The degradation of microbiological contaminants strongly depends on solar radiation and the factors that regulate its intensity, such as the depth of the effluent plume, seasons, and cloud cover. The submarine disposal of domestic sewage constitutes a low-sanitation-risk alternative regarding the contamination of bathing areas. The results based on computational modeling corroborate this alternative, showing that the coastal zone is not affected by marine sewage discharges.

The Spatial Geographies of Women Urban Runners

ABSTRACT Taking the northern suburbs of Melbourne, Australia, as a case study, we researched the running experiences of women through a feminist geography lens. Interviews with runners informed the design and interpretation of a spatial analysis of women’s running patterns in Strava Metro data. Our study showed how women runners are limited in where they run, and illuminated features of urban environments that can contribute to gendered limitations running women experience. Our approach took us beyond critiques of park management (e.g. lighting, toilets, trail surface), to eventually form findings about how urban form influences the spatial geographies of women runners. HIGHLIGHTS Women restrict where they run alone more than men do because of fear of being attacked by a man, avoiding isolated places in particular. Running is an activity in which women can feel at their most vulnerable in urban public space, as they are often alone, outside beyond daylight hours, and are seeking soft surfaced paths away from motor traffic, places where real-life passive surveillance is usually lower. Gendered differences in the use of urban space by runners can be observed in Strava Metro data. A key feature of women’s running route decision-making is that women will avoid and seek certain places based on how many other people they expect to be present there. Women runners benefit from urban forms which encourage high pedestrian activity, including medium-high urban density and pedestrian prioritised links to greenspaces that are separated from key traffic routes.