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| THE STUDY ON SPATIAL GROWTH PROCESS OF BI-POLAR WITH CORRIDOR STRUCTURES IN THE METROPOLITAN AREA——A Case of the Baltimore-Washington Region in the USA |
| WANG Li, ZONG Yue-guang, QU Xiu-li |
| The Department of Urban and Resource Sciences, Nanjing University, Nanjing 210093, China |
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Abstract Urbanization has been recognized as a ubiquitous phenomenon in the world wide especially since the second world war. The urbanization process of the metropolitan area of the Baltimore-Washington within 200 years is a typical Bi-polar growing process among corridors. By the 1790's, the major growths of urban area had been around several growth poles. By the 1890's, the urban growths had begun along several corridors from Washington and Baltimore. By the 1990's, the urban growth both along the growth poles and corridors had been called network growth. It totally connected major corridors between Washington and Baltimore in 1992. This process can be described as "point-line-net-surface growth model". This paper uses Mapinfo7.0 to create several radius of incircle and circumcircle of two regions in 200 years, and works out the rates of growth of incircle and circumcircle by employing Logistic Model, and then analyzes them contrastively. We find that both core growth and corridor growth form the urban sprawl of Baltimore and Washington, but the rates of them were different and had their own characteristic. In order to analyze the difference of urban expanding of Baltimore and Washington in more detail, this paper introduces into the model of expanding degree. we find that the spatial morphology of Washington was excelled Baltimore before 1962, after then Baltimore was more excellent. The expanding degree of Washington was only 1.51 in 1992, but Baltimore was 2.98. If the region of Washington would not take effective measures against the concentric circular sprawl of urban space, it might appear to be the construction in big mass growth as if caking on the pan, the more serious is that the expand of urban growth has suffered with increased environmental pressure because the limited environmental capacity. They expand over agriculture, wetlands, wildlands, and forests, thereby changing the physical shape of the landscape as well as the functioning state of the landscape ecosystem. In order to solve the problem,"Smart Growth" initiatives have been promoted since 1990's by increasing urban forest areas and constructing rural ecosystems in Washington. According to correlative information, Washington does not come forth the phenomena as we imaged before. It is clear that the "Smart Growth" of metropolis must be favored for the sustainable development of China metropolitan planning. Traditional studies of spatial growth of Bi-polar of growth with Corridor Structures usually use the Bi-polar of growth with Corridor Structures as a whole to study the law of spatial growing process, but this paper tries to find out the law of the spatial growth of Bi-polar of growth with Corridor Structures by contrasting the growth of cores and corridors in two regions with the radius of incircle and circumcircle.
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Received: 08 November 2004
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2006, Vol. 21 
