| Cities provide spatial contexts for populations and economic activities.The formation and development of cities represent spatial-temporal processes,which are characterized by urban land expansion to a certain extent.Determining the characteristics of urban expansion has particular significance for regional sustainable development.To achieve a better understanding of the spatial and temporal characteristics of urbanization and urban expansion of oasis cities,we conducted this study.In this paper,we selected 5 oasis cities around Tarim Basin as the study area,they were Korala,Aksu,Artux,Kashgar and Hotan.Firstly,we studied the urbanization process and its characteristics of the above 5 cities from 1990 to 2015 by using Weight Analysis method and the Principal Component Analysis method.Secondly,we employed Landsat TM/ETM+imagery data from 1990,1995,2000,2005,2010 and 2015,and extracted the land use classification data in urban built-up-area by using Supervised Classification method in ENVI4.5.Thirdly;the urban expansion information was abtained from classification images under ArcGIS10.1 environment.Then urban expansion indexes such as the expansion area,expansion proportion,expansion speed,expansion intensity,compactness and fractal dimension,were extracted.Forthly,using qualitative and quantitative methods,the driving factors of urbanization and urban spatial expansion were analyzed comprehensively from the aspects of natural geographic condition,great population growth,rapid economic development,convenient transportation and region policymaking.Finally,the relationship between urbanization and urban spatial expansion was analyzed by using Grey Relational Analysis method.The main research results indicated that:(1)The urbanization level of the 5 cities during the whole study period gradually increased,especially from 2010 the increasing trend is more significant;the population,economy and society urbanization indexes have always been a big weight in the whole urbanization processes.(2)The urban spatial expansion analysis shows:①The construction land area and its proportion were accounted for the biggest advantage ampoong the 5 land use types.②All of the 5 cities experienced that urban construction land occupied the other 4 land use types,and these land use types are countributing urban expansion to different degree.③The urban expansion area {EA)of the 5 cities are:Korla>Kashgar>Aksu>Hotan>Artux,and the values were 63.65km~2>40.50km~2>31.72km~2>17.57km~2>2.92km~2,respectively.④The expansion speed(ES)of the 5 cities are:Hotan>Korla>Aksu>Kashgar>Artux,and the values were 8.47%>6.53%>6.42%>6.00%>1.88%,respectively.⑤The comprehensive expansion index(SI)of the 5 cities are:Hotan>Aksu>Artux>Kashgar>Korla,and the values were 7.15‰>2.29‰>1.57‰>1.54%o>0.68‰,respectively.⑥ The compactiveness(C)of the 5 cities are Artux>Hotan>Aksu>Korla>Kashgar,and the values were 0.076>0.053>0.041>0.024>0.023.⑦The fractal dimension(D)of the 5 cities are Artux<Hotan<Aksu<Kashgar<Korla,and the values were 1.319<1.352<1.369<1.371<1.421.(3)The relatively flat terrain,the growth of urban population,rapid economic development,convenient transportation and the local policies are the driving factors of urbanization and urban spatial expansion.(4)The Grey Relation Analysis shows:The correlation coefficients of the urbanization to the urban spatial expansion were Korla>Hotan>Aksu>Kashgar>Artux,and the values were 0.747>0.707>0.687>0.663>0.659,the values between 0.650-0.850,whch are highly correlated.The correlation coefficients of the urban spatial eexpansion to the urbaniazation were Artux>Aksu>Korla>Hotan>Kashgar,and the values were 0.677>0.663>0.652>0.622>0.611.Among them,the correlation coefficients of Artux,Aksu and Korla were between 0.650～0.850,which are higly correlated;the correlation coefficients of Hotan and Kashgar between 0.350～0.650,moderately correlated.Therefore,there is a mutual close correlation between urbanization and urban spatial expansion. |
PDF Full Text Request