Computing the Urban Sprawl Dynamics Through Fractal Geometry
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Journal of Controller and Converters Volume 4 Issue 3 Computing the Urban Sprawl Dynamics through Fractal Geometry Nisar Ali Ph.D. Scholar, Department of Mathematical sciences, Federal Urdu University of Arts, Science & Technology, Karachi, Pakistan Email: [email protected] DOI: http://doi.org/10.5281/zenodo.3426853 Abstract Urban sprawl has become a very magnificent topic throughout the world since last decade. Various techniques, methodologies and quantitative approaches are based to measure urban sprawl in previous researches. In this research a different idea of fractal analysis is introduced to analyze the urban sprawl. In addition density gradient and sprawl index techniques have also been used to characterize the urban sprawl in Karachi. In this study, we have discussed the urban sprawl of Karachi from its first census (1951) to 2012. Massive flight of the population is recorded between 1981 and 1998 to the periphery of city Karachi. As a result central population density decreased at rapid space and population density gradient exhibits a gentle slope. Overall population density of Karachi constantly increases from 1951 to 1998 but it decreases in 2012 because large rural lands were converted into urbanized lands during 2002 to 2012. For the same six time periods, urban form of Karachi is also quantified through fractal analysis in the context of urban sprawl dynamics. Our results suggest that the fractal dimension of urban form is proportional to the urban sprawl index for the concentrated urban growth patterns. We have also tried investigating sprawl phenomena theoretically further, we have probed the causes and impacts of urban sprawl in Karachi in a given time periods. Keywords: Density gradient, form, fractal analysis, fractal dimension, quantitative approach, urban sprawl INTRODUCTION and large fiscal distinctions among Urban sprawl was initially identified in individual communities [2−4]. America during 1950s, when it was observed that population density of cities Urban sprawl and population dispersal in declined [1] and urban areas expanded Karachi city are associated with the rapid with faster rate than population growth population growth and sudden areal rate. Urban researchers coined a term growth, government policies of population “urban sprawl” for this phenomenon. A dispersal and horizontal/linear growth and clear and precise definition of Urban huge conversion of urbanized lands/areas. sprawl is absent yet. Urban sprawl is a In develop countries like United States term associated with the rapid growth of (US), Canada and United Kingdom (UK) urban area resulted loss of agricultural etc., urban sprawl is related with fast land, forest and rangeland leapfrog and expansion of suburbans. In the United commercial strip development. Other States and the United Kingdom essential features of sprawl consist of suburbanization initiated in the early 20th infinite outward extension of development, century as a result of the strategies of dominance of transportation by private population de-concentration and industrial automobiles, fragmentation of land use, decentralization [5], because of fast suburbanization the central population 2221 Page 22-34 © MAT Journals 2019. All Rights Reserved Journal of Controller and Converters Volume 4 Issue 3 dencity slope downed while population disorganized and can be stated as complex density gradient got gentle. While structure. Complex systems approaches measuring sprawl the most important behave the urban areas as dynamic, factor is the density which is a very nonlinear, dissipative, open structures [12, difficult concept because its measures vary 13]. in many ways, so it is quite worthy to clarify certain points. An alternative Euclidean geometry nearly fails to explain approach to quantifying density instead of the highly complex spatial organization, using the dwelling units per given area or but fractal analysis offers different number of people is the density approaches on the urban landscape that gradient.zzc [6−8]. Urban dynamics cause takes into account urban spatial cities grow and economies develop can be complexity [6, 14, 15]. Fractal geometry illustrated by the gradient models which and Chaos theory provide a comprehensive generalizes urban form as mono-centric. idea to understand urban development in [8]. Built sspace in urban areas is the space.complex systems and the complexity additional feature of sprawl configuration. level of morphological differences are The spatial configuration provides more undergone through Chaos theory and blueprints than the size or geometry of fractal geometry repectively. cities. These features increase the rate of the spatial expansion of metropolitan areas PREVIEW TO THE DEVELOPMENT by generating discontinuous land use PROCESS OF KARACHI patterns [9, 10] identified the dimensions Sprawling urban development in many of sprawl i.e. density, continuity, metropolitan areas throughout the world concentration, compactness, centrality, has become a very hot topic since last nuclearity, diversity, and proximity and decade and the associated conversion of latter Ewing R, [11] also generated a rural land into urban land is the similar sprawl index based on four factors that can important issue as well. Karachi being the be measured and analyzed: largest city in Pakistan facing the same important issue as its urban development Residential density and population is increasing day by day. In Neighborhood mix of homes, jobs, and the United States of America (USA), most services, of citizens like independent housing with Strength of activity centers and open space rather than apartments, downtowns, and however suburban residents worry about Accessibility of the street networks. the increasing commuting cost [5]. In the less developed countries, where percentage The density of the urban centre would rise of urban population is low and during urbanization and the population suburbanization has not achieved desired would remain heavily concentrated in the results, urban sprawl is quite important city centre with a rapid decline in problem in the mega city like Karachi settlement towards the periphery. With this especially in the absence of proper urban ongoing enhancement in economy and the infrastructure like water supply, sewerage network expansion in public transports system, mass transit, and transportation many residents would then gradually shift means. Urban growth in Karachi is towards the suburbs, which cause the different from Western cities where suburban growth is an important feature of gradual softness in density gradient of sprawl. Therefore, it is important to work population. This evidence can be seen in on spatial pattern of population Table 5 in our present case study of distribution and density gradient patterns Karachi urban sprawling. This evidence in Karachi. Karachi city started its growth that the urban development process is 23 Page 22-34 © MAT Journals 2019. All Rights Reserved Journal of Controller and Converters Volume 4 Issue 3 as recognized city from 1729 with the suburbanization and retail expansion estimated population of 1000 and area of patterns in the metropolitan areas. This 0.12 [16]. According to the census of enhancement in accessibility affected the 1951, the population of Karachi increased location of the new residential settlements to 1.6 million while in 1941 it was and the location of firms as well. The estimated 386,655 with area 115 (Census construction of huge residential apartments, 1951). This rapid enhancement in the shopping malls, elite educational institutes, population occurs soon after the creation modern towns and industries has caused the of Pakistan in 1947 because Karachi was outward expansion of the city. Due to this chosen as the first capital of the country. expansion and suburbanization movement, And soon after the independence almost 1 new sub-centers have emerged and this million people came to Karachi from India multi-center development has been thus rapid population growth and areal encouraged and supported. Thus, Karachi expansion of city took place. This rapid has been divided into 6 districts and 18 growth of the city has affected urban towns. The continuous population growth spatial development. Which lead to lessen with result of multi-centered peripheral the density gradient 1.37 to 1.16 during development has dominated the 1931 and 1951 repectively [17]. According development characteristic of the city to the census of 1961 its population Karachi. The recent housing schemes like increased to almost 1.9 million, while in Steel Town, Gulshan-e-Memar, DHA 1972 it reached to 3.4 million with an area Housing city and Behria Town has of 640 (census 1972). The population expanded the peripheral area of city more. growth and areal growth of Karachi did Such rural lands around Karachi City have not stop and it continued to increase. been converted for planned and unplanned housing, squatter settlements and factories Unlimited new housing projects like Taiser etc. Rapid conversion of rural land into Town, Khuda Ki Basti, Halkani, Shah urban land uses had been taking place during Latif Town were developed as well as the last decade (2002 to 2012). The many new squatter settlements were built construction of new flyovers had played an in peripheral land of the city. Population of important role in the sprawl of city. It is also peripheral residential areas which were observed that due to the development in developed in 1980s like Gulistan-e-Jauhar, economic conditions of