The Expansion Characteristics,Stage Pattern And Mechanism Of Construction Land In Major Urban Areas Of Asia During The Past 30 Years

The expansion of urban constn-ction land is the most obvious manifestation of urbanization in space,and is one of the important:nethods to:neasure the urbanization process.Because of the differences of geographical environment,social politics and historical development in different countries,the urbanization development speed and stage are different,thus resulting in dle discrepancy of expansion characteristics and pattern of urban construction lald.Exploring the expansion process and characteristics of construction land in main cities of different countries and summarizing developmental experience and lessons of different stage have important gniding significance to the expansion of urban construction land.For the geographical proximity in Asian countries,and as the advancing of the strategy of The Belt and Road’,China is furthering cooperation and communication with the countries alolg the Silk Road.A betler regional economic cooperation mode is built on the basis of the deep knowledge on the partner cities’urbanization process.However,form the recent research progress,study on construction land developmental characteristics of Asian cities along the Silk Road is very few.Therefore,this study selected Asian important cities of different geographical partition and development stage as the research object,ald analyzed the expansion characteristics,node and mechanism of these cites during nearly 30 years,which is aimed to grasp the urban expalsion trend,deepen the essence understanding of urbanization,clear developmental differences among different cities and provide the experience for reference to urban development in China.The study selects doruestie cities:Beijing,Shanghai and Guangzhou,abroad cities in developing countries:Kuala Lumpur,Mumbai,Tehran and Almaty,main eities in developed countries:Seoul and Tokyo to make a comparison analysis.Based on the Landsat remote sensing image data,by extracting a certain area of urban construction land,the study analyzes the overall characteristics of construction ltuid expansiol in each city region,then analyzes the stage characteristics in 1980-1990,1990-2000 and 2000-2010 of each city region from the aspects of qualtity,space and coupling characteristic.Through characteristic clustering,stage pattens of construction land in each city region are achieved.Finally,the study tries to explore the driving mechanism of quantity expansion of each city region and spatial expansion of different stage pattern from the qualitative and quantitative angle.The main conclusions of this study are as follows:(1)The overall characteristics of construction land expansion in each city region show that the city of Tokyo in highly developed country tends to be more large-scale and stable,and continuous in space.The city of Seoul tends to be saturated in city proper and develops more in the periphery.The cities in developilg countries have both similarities and differences.Beijing,Shanghai and Guangzhou have the similar characteristics whose expansiol space is very large and perform urban sprawl.Expansion in the city of Kuala Lumpur is also significant,the city proper is gradually collecting to the satellite towns.The city of Mumbai,Tehran and Almaty relatively have few expansion and exists certain limited and dominant expansiol direction.(2)The stage characteristics of construction land expansion in each city region show results of several aspects.As for the expansion strength,a general ladder is appeared that Guangzhou and Kuala Lumpur are the biggest,followed by Beijing and Shanghai,others are relatively weak.As for the expansion compactoess,more developed cities tends to be dispersing with more centers,while developing cities gelerally experience high-density expansion in the edge of core areas and then low-density sprawl.As for expansion coordination,the cities in developed countrnes tend to be shrink,and the population of the city proper decreases as the reverse urbanization progress.The cities in developing countries differ significantly.China’s cities and Kuala Lumpur have faster speed in land expansion than population,while Mumbai ald Tehran are faced with the problem of excessive urbanization that land expansion is insuficient to hold population growth.(3)Based on the characteristics of expansion strength9 compactness and coordination,stage patterns of construetion land expansion are coupled ehistered,incllding four types:’compact’,’clispersed’,’lagged’ and ’mature’,which better manifest the evolution characteristics of construction land expansion and is coordinated with the tendency of population density change with the city growth.The cities in developing countries with high expansion speed such as Beijing,Shanghai,Guangzhou and Kuala Lurupur belong to the pattern of ’compact’ in early stage and dispersed’ in the latter period,while other cities in developing countries such as Mumbai,Tehran and Almaty are more lagged expansion in latter sfage.The cities in developed countries tend to be’mature,(4)According to the development period of each city region,the macro quantity expansion is drivel by multiple factors,but the main driving force is existed.Construction land expansion in cities of Beijing,Shanghai.Guangzhou,Almaty are more influenced by economic development and Seoul and Kuala Lumpur tend to be driven primarily for planning;and Teliran ald Mumbai mainly driven by population growth as well as planning.The spatial expansion is affected by m icro location selection mechanism based on maximum benefits of choices.Different stage patterns have different driving forces.The central radiation and scale effect are the main factors in’compact’ pauettern,which promote coristruction land expansion from center to outside.The secondary center radiation and tralsportation effects become more and more obvious in ’dispersed’pattern along with the influence of scale effect.In ’lagged’ stage pattern,the driving forces are differelt transferred by the purpose of maximum benefit.The driving factor change of each stage pattern explained the process of agglomeration to diffusion to some extent in urban development lliat city is early dominated by single center,then expands by the stage of core edge spreading,traffic axial diffusion,new city expansion,and finally develops into multi centers.