| Since the reform and opening up, China is experiencing rapidurbanization process.with the planned economy to the marketeconomy, the improvement of the number of population and the levelof economic development, Chinas urbanization process and cityconstruction process has been obviously paced up. Shanghai as thelargest financial center in China, the urbanization level has been at thefirst, Shanghai urban expansion not only in Chinabut also in the worldresearch in the course of development of all have certain typicalsignificance.Using the1979,1990,2000,2009four periods of TM image data,Through the ENVI software for each period of urban expansion maps,1km*1km for a unit, analysing and revealling in the process of Shanghaiurbanization changes of land use structure characteristics,temporal-spatial characteristics, expand intensity. And the2000,2003,2006three periods ofShanghai visual interpreting data, streets as scale,analysis the twenty-first century streets of Shanghai the rapid expansionof change. And based on Shanghai urban expansion time and spacechange of factors driving force; With the CLUE-S model to simulate theShanghai2020years of the land use map, and (1999-2020) Shanghaiurban overall plan of superposition analysis. the main conclusions are asfollows:(1)1979-2009, land use structure in the study area is greatlychanged in30years.among then, urban land area is greatly increased; The farmland, green area conti nues to decli ne; Water, bare area hasincreased.(2) Urban t emporal-spatial differentiati oncharacteristicsin Shanghaisi gnificantly. urban area of Shanghai si gnif icantly changed in1979-2009, the expansi on of the urban land speeds up, the area ofexplosion. inposition, from1979to1990, the main city in the direction ofthe axis to north and expansion, the expansion of the southwestdirection speed slightly faster; and From1990to2000, north and southaxial direction continues to expand, the northeast to southwest and toexpand faster;2000to2009, in addition to the north and northeast, therest are in rapid urbanization, especially to the southwest and southeast,expansion area three or four times than before.(3) Urban expansion intensity of Shanghai,1979-1990, city extendtotal slowly, from the city center to the south and the north upexpansion.1990-2000, Shanghai allappear low-speed extended state,city center expanded approaches saturation, the thecenterofexpansionalso gradually overseas. expansionin Southwestfaster than other regions, and then inner ring to the district extensionspeed.2000-2009, Shanghai urban rapid expansion, the center cityextension to a standstill, suburban medium speed expansion, andsuburban districts into the rapid urbanization.(4) The expansion in unit of the streets in Shanghai city as follows:2000-2003, Shanghai street extended change is not very significant, inaddition to jiading、songjiang、district of pudong area, some of thisstreets on the expansion, most of the other street is slow in the expansion.2003-2006, Shanghai entered the overall medium speed extensionstages. Songjiang districts、jiading、most streets of chongming islandinthe expansion. Shanghai urban expansion transfer from the centraldistrict has to the suburbs. (5) combined with the statistic dataof Shanghai1979-2009,analyzing city driving force factors, the driving force factors of Shanghaibroadly divided into five aspects as follows: the social economic;development factors、the government decision factors、 transportationinfrastructure factors、Population growthfactors、Natural environmentalfactors. And considers the main driving force of urban expansioninShanghaiare social and economic development and governmentpolicy factors.(6) By CLUE-S model simulated three kinds of different situations ofShanghai land use in2020. And The comprehensive plan of Shanghai(1999-2020) contrast, Shanghai city land development too fast.Therefore, Shanghai should be to slow down the speed of expansion,strengthen the intensive utilization of land, protect the farmland and thearea of the greenland. |
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