Comparative Study On Intensity And Spatial Model Of Land Change In Typical Cities Of Jiangsu Province

Since 1990 s,China has been in the stage of rapid urbanization.The area of urban construction land has been expanding,and other landscape sites are becoming less and less.Taking the Nanjing and Xuzhou municipal districts of Jiangsu Province as the research area,this paper supervised and classified six remote sensing images of Nanjing and Xuzhou districts in 1990,2003 and 2016,and then superposed the classified images of three phase in the same study area.According to the classification and superposition results,the intensity of the urban land change and the representation of the spatial model are calculated for the change of construction land in the two research areas,and then the comparative analysis of two cities in 1990-2003 and 2003-2016 of the two time intervals in the city expansion.At the same time,the influence factors of the urban expansion of the research area were analyzed by using the data of the ground surface area and various driving force factors in the research area in 1990,1997,2003,2010 and 2016.The final conclusion is as follows:(1)Over the past 26 years,the area of construction land in two cities has increased rapidly.The urban expansion is more obvious,but the expansion direction is different.The Nanjing municipal district has been expanded mainly along the old urban area,while Xuzhou's district has developed mainly towards the southeast.(2)By comparing the intensity of urban land change found in two research areas,Nanjing's urban expansion is more obvious than that of Xuzhou in the two intervals from 1990-2003 to 2003-2016.The two stage of expansion is "medium speed",and the overall expansion is relatively stable.In contrast,the urban expansion of Xuzhou in the 1990-2003 interval is relatively slow,but the expansion of the 2003-2016 is relatively fast,the difference in urban land changes in the two time intervals is relatively large.But the interval between the intensity of urban expansion and the interval of the second period of urban expansion is more intense than the first interval.(3)Comparing the spatial models of urban land change in two research areas,we will find that,in the past 1990-2003,Outlying occupied the leading position in Nanjing district.In the later 2003-2016,the proportion of Edge-expansion and Infilling increased significantly,and the Outlying ratio decreased.Edge-expansion occupied the dominant.By contrast,in the early period of urban expansion in Xuzhou,the Edgeexpansion of urban expansion was relatively large,but the later Infilling expansion dominated,but it also shows a trend that the Outlying expansion is greatly decreasing.(4)By analyzing the influencing factors of urban expansion in two research areas,It can be seen that the household registration population,GDP,the length of urban pavement and some policy factors have an impact on the urban expansion of the study area.(5)In the past 26 years,the speed of urban expansion and the intensity of urban expansion have been steadily increasing in Nanjing district.For the old city,the land resources in the old urban area are limited,so it is necessary to use the land in an intensive way to make the best use of the land.For the Xuzhou district,in the past 26 years,the intensity of urban expansion is slow to fast,and the development is very unstable.Therefore,Xuzhou cannot expand the construction land area blindly in the future urban expansion.It is necessary to strictly observe the urban development plan of Xuzhou,strictly control the urban population and the area of construction land,only in this way can the urban expansion be more stable.