Ciutat dispersa

Les metròpolis actuals es troben en un profund procés de transformació, que afecta especialment a les estructures territorials de les seves perifèries. La ciutat compacta tradicional es transforma en un espai metropolità cada vegada més discontinu, dispers i fragmentat. Els processos de dispersió de la població estan creant nous espais residencials de baixes densitats.

Landscapes of urban sprawl

TeMA Journal of Land Use, Mobility and Environment (2012)

LA CITTÀ A BASSA DENSITÀ: PROBLEMI E GESTIONE

The essay explores the phenomenon of low-density city. It is divided into three main parts in which are described the characters, the changes and the forms of the phenomenon in different contexts.

In the first part are highlighted character and evolution of the phenomenon in several European and North American contexts, while the second describes the transformation and evolution of a specific context: the territorial system of the central Veneto region.

It is a particular example of sprawl occurred in the last forty years that a profound changes in physical, morphological and socio-economic characteristics of the area.

In the third part of the essay some examples of policy and planning tools for containing the land consumption and resources in a sustainable way.

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El proceso de urbanización dispersa de las metrópolis españolas, en el contexto del desarrollo urbano europeo

Mª Victoria Azcárate Luxána, David Cocero Matesanza, Antonio Fernández Fernándeza, Francisco Javier García Lázarob, Carmen Muguruza Cañasa y José Miguel Santos Preciado (2012)

En los últimos años, el modelo territorial de los países más desarrollados, por motivo de los recientes procesos de innovación tecnológica, la universalización del acceso del automóvil y el abaratamiento del coste del transporte, ha sufrido una evolución muy importante, pasando de un modelo urbano de áreas más compactas, propio de las áreas metropolitanas clásicas, a un modelo de ciudad dispersa. El trabajo que presentamos es un intento de definir los rasgos más importantes de este modelo de ciudad, a la par que realizar una reflexión sobre las características de esta nueva forma de organización urbana en el contexto territorial europeo y principales aglomeraciones urbanas de nuestro país.

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El modelo monocéntrico metropolitano frente al nuevo modelo policéntrico de la ciudad difusa

monocentriociudaddifusa

Modelo de ciudad dispersa europea
monocentriociudaddifusa2

Causes and consequences of urban growth and sprawl

Basudeb Bhatta, 2010 (2nd Chapter of “Analysis of Urban Growth and Sprawl from Remote Sensing Data”)

An overall idea about urban growth and sprawl has been provided in Chap. 1. This chapter is aimed to list the causes and consequences of urban growth and sprawl. The causes that force growth in urban areas and the causes that are responsible for undesirable pattern or process of urban growth are also essentially important for the analysis of urban growth. The consequences or the impacts of urban growth, whether ill or good, are also necessary to be understood and evaluated towards achieving a sustainable urban growth.

Galster et al. (2001) argue that sprawl as a pattern or a process is to be distinguished from the causes that bring such a pattern about, or from the consequences of such patterns. This statement clearly says that analysis of pattern and process should be differentiated from the analysis of causes and consequences. Remote sensing data are more widely used for the analysis of pattern and process rather than causes or consequences. However, some of the researchers (e.g., Ewing 1994) argue that impacts of development present a specific development patterns as undesirable, not the patterns themselves. Therefore, whether a pattern is good or bad should be analysed from the perspective of its consequences. Causes are also similarly important to know the factors that are responsible to bring such pattern. Indeed remote sensing data are not enough to analyse the causes or consequences in many instances; one should have clear understanding of causes and consequences of urban growth and sprawl to encounter the associated problems.

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La ciudad dispersa: cambios recientes en los espacios residenciales de la comunidad de Madrid

J. C. García Palomares, J. Gutiérrez Puebla (Departamento de Geografía Humana. Universidad Complutense de Madrid), 2007

Las metrópolis actuales se encuentran en un profundo proceso de transformación, que afecta especialmente a las estructuras territoriales de sus periferias. La ciudad compacta tradicional se transforma en un espacio metropolitano cada vez más discontinuo, disperso y fragmentado. Los procesos de dispersión de la población están creando nuevos espacios residenciales de bajas densidades. Este trabajo analiza aquí las características que definen los espacios residenciales de la periferia de Madrid, atendiendo al crecimiento del parque de viviendas, las tipologías edificatorias y las densidades de los espacios residenciales.

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The Compact versus the Dispersed City: History of Planning Ideas on Sofia’s Urban Form

Sonia Hirt (2007)

This article reviews the planning history of Sofia since its designation as the Bulgarian capital in 1879. It argues that Sofia’s planning has been persistently shaped by two perennial dilemmas—how to reconnect the city with nature and how to define its relationship with the region. In response to these dilemmas, different visions, shaped by both local conditions and dominant foreign theories, were proposed at different times. Some promoted a compact city, while others advocated a dispersed form. The case of Sofia demonstrates the significance of the city-nature and the cityregion relationships in the evolution of planning thought. It also points to the difficulties that arise when local ideas of how to organize these relationships are inspired by international models made for cities with different historic experiences.

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Compact, dispersed, fragmented, extensive? A comparison of urban growth in twenty-five global cities using remotely sensed data, pattern metrics and census information

Annemarie Schneider and Curtis E. Woodcock (2006)

Despite growing recognition of the important role of cities in economic, political and environmental systems across the world, comparative, global-scale research on cities is severely limited. This paper examines the similarities and differences in urban form and growth that have occurred across 25 mid-sized cities from different geographical settings and levels of economic development. The results reveal four city types: lowgrowth cities with modest rates of infi lling; high-growth cities with rapid, fragmented development; expansive-growth cities with extensive dispersion at low population densities; and frantic-growth cities with extraordinary land conversion rates at high population densities. Although all 25 cities are expanding, the results suggest that cities outside the US do not exhibit the dispersed spatial forms characteristic of American urban sprawl.

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The dynamics of urban sprawl

Michael Batty, Yichun Xie, Yhanli Sun (1999)

This paper introduces a framework for understanding the dynamics of urban growth, particularly the continuing problem of urban sprawl. The models we present are based on transitions from vacant land to established development. We propose that the essential mechanism of transition is analogous to the way an epidemic is generated within a susceptible population, with waves of development being generated from the conversion of available land to new development and redevelopment through the aging process. We first outline the standard aggregate model in differential equation form, showing how different variants (including logistic, exponential, predator-prey models) can be derived for various urban growth situations. We then generalize the model to a spatial system and show how sprawl can be conceived as a process of both interaction/reaction and diffusion. We operationalize the model as a cellular automata (CA) which implies that diffusion is entirely local, and we then illustrate how waves of development and redevelopment characterizing both sprawl and aging of the existing urban stock, can be simulated. Finally we show how the model can be adapted to a real urban situation – the Ann Arbor area in Eastern Michigan – where we demonstrate how waves of development are absorbed and modified by particular historical contingencies associated with the pre-existing urban structure.

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Urban Sprawl Modelling. The Case of Sanandaj City, Iran

Sassan Mohammady, Mahmoud Reza Delavar

World urban population has dramatically increased from 22,9% in 1985 to 53% in 2013 fact that has caused unprecedented urban environmental destruction and shortage of infrastructure needed to support the population. In terms of the pressure on the built environment, urban sprawl increases the financial and environmental costs associated with infrastructure, waste disposal, energy consumption and the use of natural resources. Urban sprawl causes much damage to the natural environment by creating and furthering the spread of pollution. Thus, it becomes necessary to monitor, analyze and model the city growth. Efforts have been made to predict potential urban development in accordance with the existing and/or planned infrastructure based on smart city development plans. A number of models have been employed to detect urban land use/cover changes considering the various known drivers of land use change. The case study area is the city of Sanandaj in the west of Iran. In this study, we used Particle Swarm Optimization algorithm for modelling the urban sprawl during 1987-2000, and we employed the Landsat imageries acquired in 1987 and 2000 for modelling urban sprawl in this area for the period 1987-2000. We also considered a number of influencing factors to predict the potential urban growth modelling including the following: distance to street, distance to district centre, distance to developed area, distance to green space, slope and the number of urban cell in a 3*3 neighbourhood. We used Kappa statistics for an accurate assessment in order to compare the simulated map in 2000 with the real one.