Spatial Patterns Of Urban Development Research Articles

Retreat from flood zones: Simulating land use changes in response to compound flood risk in coastal communities

Coastal communities are increasingly vulnerable due to sea level rise and population growth. Managed retreat is commonly recognized as a strategy that yields multifaced benefits in community adaptation. However, limited studies have explored the cumulative effects of sea level rise, population migration, and managed retreat on the community resilience. This study presents a parcel-level land use change model to analysis land-based flood mitigation strategies in Galveston County, Texas. The developed model integrates a Gradient Boosting Decision Tree with a flood risk model and diverse datasets. Our model results reveal the spatial patterns of urban development in Galveston under different relocation policies and the compounding impacts of sea level rise and population growth. Our findings illustrate that elevating the first floors of buildings can significantly mitigate flood risks and associated relocation costs. The private adaptation measure, together with government-led buyout policies, could foster a shift toward more resilient urban development and yield a more affordable relocation strategy. Our findings emphasize the need for a multidisciplinary approach in building resilient coastal communities, particularly in the face of escalating climate risks in local communities.

Modelling transitions in sealed surface cover fraction with Quantitative State Cellular Automata

Cellular Automata (CA) applications simulating urban processes generally employ discrete land-use classes to characterise the physical environment. Yet there is an increasing demand for urban land cover models simulating quantitative change at the sub-cell level. The proposed Quantitative State Cellular Automata model (QCA) addresses this issue by relaxing part of the CA definition and considering real-valued quantitative cell states reflecting a physically meaningful measure. QCA entails two components of change: transition potential and quantity of change. The potential component addresses the likelihood of any change occurring in a cell, whereas the quantity component estimates the magnitude of change. The QCA concept is illustrated for Sealed Surface Density (SSD) transitions in Brussels and part of Flanders (Belgium). A Mutual Information (MI) approach is used to define the neighbourhood interaction framework. The QCA model is respectively calibrated and validated using Landsat-derived 1987–2001 and 2001–2013 SSD change on 30 m resolution. The results show that QCA successfully emulates spatial patterns of urban development, and significantly outperforms a random model in terms of quantitative and spatial distribution of SSD change. Further improvements can be achieved by explicitly integrating socio-economic information in the proposed workflow.

Future urban development exacerbates coastal exposure in the Mediterranean

Changes in the spatial patterns and rate of urban development will be one of the main determinants of future coastal flood risk. Existing spatial projections of urban extent are, however, often available at coarse spatial resolutions, local geographical scales or for short time horizons, which limits their suitability for broad-scale coastal flood impact assessments. Here, we present a new set of spatially explicit projections of urban extent for ten countries in the Mediterranean, consistent with the Shared Socioeconomic Pathways (SSPs). To model plausible future urban development, we develop an Urban Change Model, which uses input variables such as elevation, population density or road network and an artificial neural network to project urban development on a regional scale. The developed future projections for the five SSPs indicate that accounting for the spatial patterns of urban development can lead to significant differences in the assessment of future coastal urban exposure. The increase in exposure in the Extended Low Elevation Coastal Zone (E-LECZ = area below 20 m of elevation) until 2100 can vary, by up to 104%, depending on the urban development scenario chosen. This finding highlights that accounting for urban development in long-term adaptation planning, e.g. in the form of land-use planning, can be an effective measure for reducing future coastal flood risk on a regional scale.

Modeling the trade-offs between urban development and ecological process based on landscape multi-functionality and regional ecological networks

The process of urbanization and urban land use conversion inevitably disturbs the structure and function of ecosystems and their capacity to provide ecosystem services. Integrating ecosystem services into effective policies and planning at the regional scale to achieve sustainable urban development is still a challenge. The goal of this research is to optimize spatial patterns of urban development by assessing and comparing multiple trade-off scenarios between ecological processes and urban expansion, incorporating planning and design into spatially explicit methods, and integrating ecosystem services into decision-making procedures. We develop a conceptual framework for regional urban-ecological sustainability with six steps: pattern recognition, landscape process, problem diagnosis, integrated ecological network, urbanization simulation, and decision-support. We apply this framework to a case in which planning and design have followed the rational-comprehensive approach. Results demonstrate that landscape multi-functionality and regional ecological networks are significantly improved using our integrated approach to planning and design, because it provides vital information for regional planning to cope with the urgent need for ecological protection and urban development. By comparing urban growth under three scenarios, we found that the trade-off scenario based on ecological conservation and restoration (medium security level) resolved conflict more effectively, which restricted urban expansion on land of high ecological importance by constructing regional ecological networks. In addition, using field survey and species distribution model approaches, we design plant community types with complementary tree, shrub, and herb species as part of the decision-making procedure, which can restore zonal vegetation and the hydrological cycle in rugged mountain regions. The research concludes that regional urban-ecological sustainability based on scientific assessment, planning, and design provides a rational basis for sustainable urban development and landscape management.

Simulating the impact of developers’ capital possession on urban development across a megacity: An agent-based approach

The spatial decisions of land developers are known to play a significant role in driving urban expansion into previously undeveloped areas. This is especially the case in developing country contexts. Using the Jakarta Metropolitan Area as the case study context, we model the impact of capital possession by land developers on the location selection and unveil the way in which this exerts an effect on the spatial patterns of urban development. Through a hybrid agent-based and microeconomic modelling approach, different scenarios of capital possession and loans are simulated. Results show that areas with high values of return and low development costs are most likely to emerge as targeted locales. In order to result in measurable impact on the Jakarta Metropolitan Area urban footprint, developers need to possess a minimum capital investment of US$375 m allied with a 75% lending capacity. Results also reveal that the impact of the large land developers – those with in excess of US$750 m in capital that bring higher levels of lending leverage – extend the urban footprint in more predictable ways compared to land developers with less capital and lending capacity. Our study demonstrates the value of adopting an agent-based model to explore how human decisions at the individual scale can influence the emergence of new urban forms in a rapidly developing metropolitan region.

Urban Expansion in Ethiopia from 1987 to 2017: Characteristics, Spatial Patterns, and Driving Forces

Rapid urban growth in major cities of a country poses challenges for sustainable development. Particularly in Africa, the process of rapid urbanization is little understood and research is mostly limited to single cities. Thus, this study provides a comprehensive comparative analysis of the growth and spatial patterns of urban development in the three major cities of Ethiopia (Addis Ababa, Adama, and Hawassa) from 1987 to 2017. Also, the applicability of diffusion and coalescence theory on the evolution of these cities has been tested. Remote sensing and GIS technologies were combined with spatial metrics and morphological analysis was employed to undertake this study. The result revealed that all the studied cities experienced accelerated growth in the urbanized areas, but the cities with a larger initial urbanized size were associated with lower expansion rates. Differences in extent and direction of expansion in each city were mostly related to physical features, urban master plans, and policies, with an increase in the irregularity and dispersion of urban growth, representing strong evidence of urban sprawl. The spatiotemporal analysis confirmed that the urbanization processes of Addis Ababa and Adama were consistent and Hawassa city diverged from expectations based on diffusion and coalescence theory. In general, large cities with strong economic growth in a country fail to effectively control the scattered nature of urban growth, thus requiring aggressive policy intervention. The approach used in this study permits a deeper exploration of urban development patterns and the identification of priority areas for effective urban planning and management.

Spatial Pattern Evolution and Optimization of Urban System in the Yangtze River Economic Belt, China, Based on DMSP-OLS Night Light Data

It is of great significance to research the spatial pattern of the urban system of the Yangtze River economic belt to analyze the characteristics and laws of the spatial structure of the Yangtze River economic belt and to promote the optimal development of the urban system of the Yangtze River economic zone. In this paper, the time data of the Yangtze River economic zone are corrected using Landsat satellite data and the clustering analysis method. The threshold of the urban built area is obtained by comparing the auxiliary data with other auxiliary data. Based on this threshold, a total of eight typical landscape pattern indicators—including the total area of the landscape, the total patch number, and the aggregation index—are used, and then FRAG-STATS 4.2 software is used to analyze the spatial pattern of urban development in the Yangtze River economic zone from 1992 to 2013. The results show the following: (1) During the period from 1992 to 2013, the urbanization of the Yangtze River economic zone expanded rapidly; the area of urban built-up area increased by a factor of 9.68, the number of patches increased by a factor of 2.39, and the patch density increased greatly, indicating that the Yangtze River economic zone, with an increasing number of towns and urban areas, continues to expand. (2) The complexity of the landscape patch shape gradually increased, the small and medium-sized cities continued to grow, more small towns emerged, and the total length of the border and the average density had average annual growth rates of 21.56% and 21.58%; the degree of aggregation and the mutual influence are increasing. (3) The maximum plaque index and the aggregation index show an overall declining trend. However, there are some fluctuations and disorder in the process of evolution, such as the total area of the landscape, the total patch number and the total patch density, which reflects that the Yangtze River economic zone is in the process of urbanization and has irregular and disordered characteristics.

A new approach for urban-rural fringe identification: Integrating impervious surface area and spatial continuous wavelet transform

Urban-rural fringe is the frontier of urban expansion and the most dynamic area in urban region. Identifying the urban-rural fringe accurately is of great significance, as it helps to measure the extent of urbanization and its environmental effects from the urban-rural contrast perspective. However, traditional studies with spatial discrete data and threshold methods make it difficult to identify its boundary objectively and accurately. To solve this problem, a new approach was proposed in this study, integrating the spatial continuous data of impervious surface area (ISA) and the method of spatial continuous wavelet transform (SCWT). Taking Beijing City, one of the largest city in China, as a case, this study identified the boundary of urban-rural fringe, which extended mainly in the southwestern and northeastern direction, with the area increased by 18.75% between 2009 and 2014. The accuracy of the identification result was verified by spatial differentiation characteristics of nighttime light and normalized difference vegetation index. Meanwhile, when compared with the subjective threshold method, it showed that SCWT could identify the fringe more accurately. And the ISA based identification result was more consistent with the actual spatial patterns of urban development in Beijing City than land use degree index based one, which showed the remotely sensed spatial continuous data performed more effectively well on identifying the urban-rural fringe. The proposed approach can identify the urban-rural fringe directly from remote sensing images, which is of great significance to quickly urbanization monitoring and thus sustainable urban planning and management.

Landscape patterns of development under two alternative scenarios: Implications for conservation

The spatial pattern of urban development has important ecological and conservation implications. Urban sprawl, characterized by scattered and low-density urban development, is commonly criticized for its negative ecological impact. In response, growth management policies have been proposed in order to promote compact development, which is generally considered more favorable from an ecological perspective. Spatial simulations of land cover change are useful for comparing urban development scenarios and their potential effects. One aspect that has not received much attention is how the rate of development may affect differences between compact development and urban sprawl in terms of their potential impact to biodiversity conservation at the landscape scale. Our goal in this study was to compare the spatial pattern and landscape-scale conservation and ecological implications of sprawling development (expected under unregulated development) versus compact development (promoted by growth management policies) at different development rates. We focused on Israel's Mediterranean region—a region characterized by high human population density and heterogeneous land cover. Using a cellular automata model, DINAMICA-EGO, we calibrated and validated an urban development model for the period between 1998 and 2007. Using this period as a reference, we simulated two scenarios 20 years into the future: unregulated (resulting in a more sprawling development pattern) versus regulated development (resulting in a more compact development pattern). For each scenario we analyzed a range of development rates, and compared built-up area patterns, and several landscape-level attributes of natural habitats, conservation priority areas, and protected areas. We found that at development rates comparable to those observed during 1998–2007, there was no major difference between the two scenarios. At higher development rates, some differences between the scenarios emerged: natural core areas were more fragmented and smaller in their extent, and a higher proportion of conservation priority areas were expected to undergo development in the unregulated scenario. Overall, the regulated scenario was more favorable for conservation. Since the regulated and unregulated scenarios exhibited only minor differences in lower development rates, modifications to policy measures included in the regulated scenario should be considered in order improve its effectiveness.

Human-ignited wildfire patterns and responses to policy shifts

Development of efficient forest wildfire policies requires an understanding of the underlying reasons behind forest fire occurrences. Globally, there is a close relationship between forest wildfires and human activities; most wildfires are human events due to negligence (e.g., agricultural burning escapes) and deliberate actions (e.g., vandalism, pyromania, revenge, land use change attempts). We model the risk of wildfire as a function of the spatial pattern of urban development and the abandonment/intensity of agricultural and forestry activities, while controlling for biophysical and climatic factors. We use a count data approach to model deliberately set fires in Galicia, N.W. Spain, where wildfire is a significant threat to forest ecosystems, with nearly 100,000 wildfires recorded during a thirteen-year period (1999–2011). The spatial units of analysis are more than 3600 parishes. Data for the human influences are derived from fine-resolution maps of wildland–urban interface (WUI), housing spatial arrangements, road density, forest ownership, and vegetation type. We found wildfire risk to be higher where there are human populations and development/urbanisation pressure, as well as in unattended forest areas due to both rural exodus and a fragmented forest ownership structure that complicates the profitability of forestry practices. To better help direct management efforts, parameter estimates from our model were used to predict wildfire counts under alternative scenarios that account for variation across space on future land-use conditions. Policies that incentivize cooperative forest management and that constrain urban development in wildlands at hotspot fire locations are shown to reduce wildfire risk. Our results highlight the need for spatially targeted fire management strategies.

FORUM: Sharing or sparing? How should we grow the world's cities?

Summary There has long been a debate amongst conservation biologists about how agricultural land use should be distributed spatially. Advocates of land sparing argue that high‐intensity food production on small units of land will conserve more natural habitat than low‐intensity farming spread across larger areas. Others argue that less intensive production over a greater area of land will reduce the overall load of human stressors upon ecosystems. Although agricultural and urban systems have traditionally been considered as different fields of research, there are strong parallels between the two landscapes in the patterns of their spatial configuration and the trade‐offs associated with their development. Continued and rapid urbanization, with associated losses in vegetation, highlights the need for a uniting spatial framework to assess the ecological impacts of urbanization. Here, we apply some of the thinking emerging from the agricultural land‐sparing debate to urbanization, review the similarities and differences between the two systems and set out a research agenda. Intensification of urban systems to increase housing density leads to buildings being interspersed with small tracts of natural or semi‐natural habitat patches (e.g. forest patches, parks). Urban extensification, on the other hand, is characterized by sprawling suburbanization with less concentrated, more distributed green space, often predominantly in the form of backyard or streetscape vegetation. We argue that regional scale analyses are urgently needed to determine which of these patterns of urban growth has a lower overall impact on biodiversity and to explore the geographical and taxonomic variation in the most ecologically appropriate city layout. Synthesis and applications. The spatial pattern of urban development will affect biodiversity conservation within and beyond a city's borders. We chart the early progress of empirical work on the land‐sparing debate in an urban context and suggest that to yield development patterns that minimize overall ecological impact, urban planners must work at the scale of at least the entire city rather than on a case‐by‐case basis.

Mapping Urbanization Dynamics in Major Cities of Colombia, Ecuador, Perú, and Bolivia Using Night-Time Satellite Imagery

By 2050, 90% of the population in Latin America will live in cities, but there is a lack of up-to-date spatial information about the urban extent and patterns of urbanization in cities of this region. In this study, we analyzed population growth, urban density and urbanization dynamics between 1992 and 2009 in the major cities of Bolivia, Colombia, Ecuador and Perú using Google Earth and DMSP/OLS night-time lights imagery. We used Google Earth to map the urban extent, and time series of night-time lights to analyze spatial patterns of urban development. The dominant urban development patterns were: high-density compact in Bogotá, Cali, Guayaquil, and Medellín; high-density expansive growth in La Paz/El Alto; low-density expansive in Quito and Santa Cruz; and a mix of high-density compact and suburban growth in Lima. Urban growth occurred largely along the periphery of cities, influenced by the local landscape and by demographic and socioeconomic factors such as immigration and housing prices. Urban density in Colombia (>20,000 per/km2) was among the highest in the world. Future growth in the region will probably be characterized by densification and slow urban expansion. This study also validates the utility of Google Earth and night-time lights for monitoring urbanization.

The impact of urban development on hydrologic regime from catchment to basin scales

This study examines the role of urban spatial development on hydrologic response at both catchment (sub-grid) and river basin (between grid) scales in central Indiana. At the catchment scale, effective impervious area (EIA) was estimated using high density urban area and the patch size of low density urban area. The impact of urban spatial arrangement on floods was investigated using the estimated EIA for the entire White River basin, Indiana, as input to the Variable Infiltration Capacity (VIC) hydrology model with urban representation. A geographic information systems (GIS)-based routing scheme was introduced to the VIC model to route the total runoff. Seven theoretical scenarios were developed with equal urban area distributed in different isochrone zones. For return periods up to and including 100-year, the flood peaks at the basin outlet are largest if the travel time from urban cells is approximate to the mode of all pixels’ travel time (plus the time for runoff rate to reach its maximum in a storm event) of the basin. Flood peaks tend to be smaller and arrive earlier with urbanization if development occurs in areas with shorter travel time, so the largest impacts of urbanization are not necessarily seen immediately downstream of the development. This research demonstrated that the spatial pattern of urban development can affect the hydrologic regime by influencing the hydrologic connectivity of urban area at a catchment scale, while at the river basin scale it is the travel time of urban location that controls flood patterns.

Spatial Patterns of Urban Development from Optimization of Flood Peaks and Imperviousness-Based Measures

Urban development within a watershed can take on a wide and diverse range of spatial patterns. The terms “sprawl” and “clustered” development, for example, are frequent in the literature, spanning the spectrum of possible spatial patterns of urban development. The relationship between flood conditions and the spatial distribution of the urban development has been poorly studied, often because of limitations in streamflow data availability or the common use of lumped watershed models in urban hydrologic modeling. We study this relationship with an optimization-based approach that accounts directly for the spatial distribution of imperviousness to investigate how the urban spatial pattern will affect flood peaks and how it can be used to reduce or minimize undesirable impacts to water resources. We employ several water resources-based objective functions to perform optimizations that result in distinct spatial patterns of urbanization showing characteristics of both sprawl and clustered development, dependi...

Spatial Impacts of Locally Enacted Growth Controls: The San Francisco Bay Region in the 1980s

In this paper the regionwide, spatial consequences of locally enacted growth controls are examined on the basis of a case study of the San Francisco Bay Region. A quasi-experimental methodology is employed. An ex post projection of population distribution among the region's cities in 1990 is generated by means of a model that represents the before growth control urban structure. A comparison is then made between the projected distribution and the actual distribution depicted by the 1990 census data. The differences, indexed as percentage projection errors, provide an empirical basis for assessing the impacts of local growth-control policies. Statistical analyses of the projection errors indicate that the local policies have caused a major redistribution of population growth from growth-controlled cities to the rest of the region. Geographic information systems-based spatial analyses of the projection errors suggest that the spatial process of growth control is driven primarily by NIMBYism. The main conclusions are that: (1) the existing decentralized system of growth management has created a spatial pattern of urban development that has undesirable economic and distributional effects; and (2) a carefully developed coordinated regional system of growth management is preferable because many critical growth problems can be addressed appropriately only at the regional or metropolitan level.

Location and History as Determinants of Urban Residential Density

Dynamic models of urban residential location have been widely used in recent years to explain spatial patterns of urban development and residential density. However, there has been little empirical evidence of their superiority in accounting for observed density patterns compared with long-run equilibrium location models or pure historical models that ignore the influence of location as a determinant of density. The test developed and applied in this paper demonstrates the superior explanatory power of dynamic models and yields plausible estimates of changes over time in equilibrium densities.