Research On The Characteristics And Driving Forces Of Urbanexpansion In Zhangye City Based On RS

Urbanization is the inevitable result of the rapid development of social economy,and the development speed of social economy will also affect the progress of regional urbanization.One of the typical characteristics of urbanization is that urban construction area will change in different time periods,and urban construction area may change in a positive or negative direction.Urban expansion is a dynamic process in time and space simultaneously.Due to the influence of macro policies,social economy,population,geographical location,transportation,ecology,history and culture,the expansion process of different cities always shows unique expansion characteristics in the same process.Sorting out the dynamic change rules of urban expansion in different time periods can provide more scientific theoretical basis for realizing scientific and rational regional urban management,guiding sustainable urban development by seeking advantages and avoiding disadvantages,and rational planning and comprehensive management.Remote sensing images,topographic maps and socio-economic statistics of Zhangye city from 1980 to 2018 are used as data sources in this paper.With RS and GIS as the technical support,the ganzhou district and Gaotai County,which are the most representative areas in Zhangye City,are selected as the typical experimental areas,and the boundary data of urban construction in different years of these two typical areas are extracted by visual interpretation judgment method.Combined with the urban expansion velocity index,expansion intensity index and mass center migration model,the dynamic change of urban expansion and the law of future development of urban construction in the past 40 years are analyzed.Finally,the main driving factors affecting the urban expansion of Zhangye city are analyzed in combination with socio-economic,population,government macro-policy,geographical location and geographical environment.The main research conclusions are as follows:⑴Analysis of dynamic changes of urban space expansion and its future development characteristics.In 2018,the urban area built in 1980 in Ganzhou District and Gaotai County increased by nearly 3 times and 6 times respectively,and the area of the built-up area increased significantly with a relatively large change range.Combination with relevant data,the city built urban area expansion change is divided into three different stages,can be found,ganzhou district,1980-1995 and 2000-2018,the city built the city all positive expansion increase(area)of stage,only 1995-2000 for negative expansion area(cut),gaotai county city was built in 1980-2000 urban area in the change of phase,2005-2018 are all dealing with positive expansion stage;The intensity of urban expansion shows that The intensity of urban expansion in Ganzhou district and Gaotai County also presents different laws in stages,but both of them show a common change characteristic,that is,with the rapid development of social economy,the intensity of urban expansion gradually increases the change trend.It can be seen from the analysis of the migration rule of the center of mass in the built-up areas of the two counties that the overall equilibrium degree of urban expansion and development in Ganzhou district is relatively better than that in Gaotai County.The simulation results of urban urban development based on land use type also show that this method is feasible and the urban urban development in the two regions will still be in a positive expansion in the future.⑵Research on the influencing factors and driving mechanism of urban space expansion.Combined with the research period of social and economic and population data,corresponding factors,such as government policy and planning for the whole process of extension of driving force in the region of the macro,meso and micro scales to make in-depth analysis,factor analysis of the government policy and planning,road traffic condition,natural geographical environment,social economic and demographic factors are the main factors affecting alkaline saline city spatial expansion.Among them,the national development strategy and the amplitude of the adjustment of the urban master plan play a regulating role in the urban space expansion.Road traffic conditions have obvious traction in urban space expansion,the rapid development of urban economy and the increase of population are the most direct and main driving forces.The physical geographical environment conditions determine the overall pattern of urban development and play a certain role in limiting;The above influencing factors can be summarized as the government policy and planning control force,the traction of road traffic conditions,the driving force of urban economy and population growth,and the limiting force of physical geographical environment.Moreover,the main driving forces at different stages are different.