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Research On The Measurement, Mechanism And Control Strategy Of Urban Land Sprawl By Using GIS

Posted on:2011-03-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:K FengFull Text:PDF
GTID:1119360302499713Subject:Land Resource Management
Abstract/Summary:PDF Full Text Request
Since its appearance, urban land sprawl as a hot topic has been got wide attention. So far, plentiful research about it has been conducted in western countries, including the concept, impact, mechanism, measurement and control strategy. However, in China, it is still at the initial stage. Existing literatures mainly focused on the experience review, lacking quantitative study and systematic analysis. Meanwhile, there is great disputation about this phenomenon in domestic academia. Even worse, there is still no agreement on whether it exists or not. Therefore, special attention must be paid to when conducting research in this field.Berlin (2002) ever made a hypothesis generally accepted by academia:When the land consumption growth rate caused by urban development exceeded the population growth rate, it indicates the starting of urban land sprawl. Based on this, I believe that urban land sprawl is a global phenomenon, with no exception for China. The difference is that the research on the phenomenon should be conducted according to the local conditions.With rapid urbanization and economic transition, some typical characteristics of urban land sprawl in western countries also occur in China. For example, inefficient land use, disorder of urban expansion, scattered and leapfrogs development, traffic congestion and loss of open air are apparent in China. These negative impacts not only ruin the environment and increased the travel cost, but also hamper urban healthy development. Furthermore, the domestic institutional arrangement varies greatly with that of western, which inevitably leads to much difference in the characteristics and mechanism of this phenomenon. So we need to investigate urban land sprawl deeply. Taking Hangzhou as an example, this dissertation mainly discussed how to measure it, and tried to find the internal mechanism and effective control strategy. Finally, some countermeasures and suggestions were put forward, mainly including urban growth boundary (UGB) and transferable development rights (TDR).First, the concept was reconstructed. Using data such as economy, population, traffic and planning, this dissertation carried out detailed comparison and analysis. We could find that there were not only some commonalities, but also some differences in the characteristics of urban land sprawl at home and abroad. Then, a new definition was given out. "Chinese urban land sprawl" is a resonance phenomenon of suburbanization and urbanization, with chaotic expansion of construction land, traffic congestion and great loss of green space and farmland.Second, the quantitative measurement was conducted. Based on the characteristics of China urban land sprawl, new multi-index measurement system was reconstructed. Then, combining with five Landsat thematic mapper(TM) satellite images of 1982,1991,1996,2000 and 2005, census data, present land-use map and other supporting data, the extent of urban land sprawl in Hangzhou's main city zone (Shangcheng, Xiacheng, Xihu, Gongshu, Jianggan, Binjiang) was measured as an empirical study. Results showed that:(1) the population reduced gradually from urban center to suburb; (2) the pattern of construction land and farmland was increasingly becoming fragmentized and irregular; (3) low growth efficiency such as leapfrog development had negative impacts on agriculture, environment and city life. Besides, the urban land sprawl of Hangzhou had shown a typical stage characteristic.Third, the mechanism was explored. At present, although the mechanism explanations of urban land sprawl in west academia was rich, the focus was still on the market-oriented. However, there are many differences between China and western countries in many aspects such as the urbanization process, the land ownership system, and the marketization level. Therefore, west explanations could not be copied without any innovation. After summing up, we found that this phenomenon in China was mainly caused by system arrangement, rather than market power, including frequent administrative division adjustment, low-cost land requisition system and the blindfold construction of economic development zone. They were all characterized by government failure and products of system defects such as unclear property rights and political reform lags.Fourth, the control strategy was assessed and given out. To solve these problems and utilize land resource rationally, there is a tradition of managing urban growth through land use regulation tools, especially as land use planning in China. It is quite similar to the western policy named "growth management", both of which are system arrangement to control urban sprawl through location, scale and time. At present, policy evaluation on land use planning in our country only focused on the comparison between planned indices from beginning to end, lacking sense of space. Combing with literature review, the method of "boundary evaluation" was introduced. Based on the remote sensing (RS) and geographic information system (GIS) analysis, this research examined the control effectiveness of UCBs (Urban Construction Boundary). Three indicators on boundary control were proposed, including the effectiveness of boundary containment, land inventory sufficiency and illegal adjacent development to the UCBs. Results showed that:(1) the UCBs was so limited in guiding urban growth that most new development occurred outside. The scale of new development land outside UCBs was 33.9 km2 and that inside UCBs was 29.1 km2; (2) many new growths occurred near the boundary. In details, a total of 66.3 kilometers UCBs emerged the edge-type land development, which accounted for 28% of total length (239.3 km); (3) the area encompassed by the UCBs might not be large enough to accommodate new development. The frustration of the urban growth control through the UCBs mainly resulted from the lack of a transparent system for urban land use planning and control to provide sufficient information, the limitation of the traditional land use prediction method to consider contingencies, and the absence of a mechanism to monitor and adjust the UCBs to respond just in time to urban change. In the future, there is still much room for improvement through policy such as UGB and TDR.Possible innovations:(1) Carefully clarified the similarities and difference of urban land sprawl at home and abroad, thus constructed a three-dimensional measurement system consisted of nine indicators; (2) interpreted the inherent mechanism of Hangzhou's sprawl primly from land institutional arrangement; (3) carried out empirical studies on boundary evaluation method, and achieved a combination of graphics and data. Of course, limited by data and time, there was still much inadequacy needed to be perfected in the future.
Keywords/Search Tags:urban land sprawl, quantitative measurement, inherent mechanism, control strategy
PDF Full Text Request
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