Research On Urban Expansion And Driving Force Of Urumqi Based On Remote Sensing

As an inevitable trend of worldwide development,urbanization is an important guarantee for the prosperity of various cities,and urban spatial expansion is a typical manifestation in the process of urbanization.Urban space is composed of many elements such as material environment,functional activities and cultural values,which is difficult to sort out.With the influx of population into the city,The continuous expansion of urban scale adds more problems to the healthy development of urban space.Once urban space expands in disorder,the problem of urban diseases will inevitably occur:1)Other land resources in the city were occupied;2)The low utilization rate of urban land lead to the phenomenon of"ghost city"with high vacancy rate of housing;3)Urban spatial resources didn't match;4)Urban pollution was serious.These not only affects people's production and life,but also restricts the rapid development of the national economy.Therefore,it is particularly important to study the urban expansion and its driving factors to provide reference basis for the rational development planning of the city.The paper regarded Xin Jiang Urumqi city as research area,based on Landsat series remote sensing images and DEM elevation data,through hierarchical removal method,a variety of remote sensing indexes are combined to extract 7 phases of Urumqi built-up area data in 1989,1993,1998,2003,2008,2013 and 2018.Then,statistics of the area and perimeter of the built-up area calculate the expansion speed and intensity,elasticity coefficient,compactness,city center of gravity and the area of upward expansion of Urumqi in each period,and using the grey correlation analysis method to determine the correlation strength of each influencing factor.Finally,This paper summarizes the problems faced by Urumqi in the process of urbanization,and puts forward corresponding integration suggestions.The Key findings of the paper are as follows:(1)Based on the comparison and analysis of NDBI,IBI,EIBI,the combination of multi-remote sensing and slope information,the results show that the combination of multi-remote sensing and slope information method has the highest accuracy.(2)Spatial and temporal characteristics of urban expansion in Urumqi:In general,the built-up area of Urumqi expanded from 62.68 km~2in 1989 to 449.283 km~2in2018,with a total growth of 386.6 km~2in the past 30 years,realizing leapfrog development.During 1989-2018,Urumqi also showed the urban characteristics of low expansion intensity,high elasticity coefficient and low compactness,which indicated that the urban spatial structure of Urumqi was loose,and the land urbanization was higher than the population urbanization in the process of urban expansion.In terms of the transfer of urban center of gravity,Urumqi's urban center of gravity was located in the south of the city in 1989,and gradually moved to the north.In 1998-2003,2003-2008,the transfer distance of the center of gravity was the largest in 10 years.In both stages,the transfer distance was 1666.88m and 2033.22m respectively.In the two stages,the city expanded to the northwest.In terms of the expansion area in all directions,from 1989 to 2018 as a whole,the main expansion directions are from west to northwest,from northwest to north,and from north to northeast,accounting for71.3%of the total urban expansion area.(3)Driving force analysis of urban expansion:According to the 26 index systems of 7 categories,the influence factors were selected and the correlation degree intensity was calculated.Overall,economy was the main factor of promoting urban expansion,followed by health care and education.(4)Based on the analysis of the spatial and temporal characteristics of Urumqi's urban expansion and the study of the driving forces of urban expansion,this paper summarizes and analyzes the problems faced in the process of urban expansion.The industrial layout of the northern industrial zone is chaotic,the traffic in the southern city is crowded,the traffic from the south to the north and from the east to the west is poor,the urban spatial structure is loose,and the environmental quality and quantity of urban green space need to be improved.In view of the existing problems,the corresponding integration opinions are put forward:reasonably planning the urban space and industrial structure,improving the transportation mechanism,perfecting the urban public facilities,optimizing the environmental ecosystem,and realizing the healthy development of the city.