Spatial Expansion Of Core Cities In Northeast Sichuan And Study On Influence Mechanism

By exploring the urbanization process of Dazhou under specific terrain conditions,Providing scientific basis for Land use Planning,Urban Master Planning and Land and Spatial Planning of such cities.The three Landsat series remote sensing images were used to gain the plot of construction land,by using ArcGIS,ENVI and SPSS.And the scope of the urban building area of Dazhou is drawn by referring to the high resolution remote sensing images of the corresponding period and the statistical data of the established areas over the years.This paper analyzes the characteristics and types of urban expansion in Dazhou during the two periods from 1995 to 2005?2005 to 2015,and the influence mechanism of the basic terrain factors and social-economic data to urban spatial expansion.On the basis of combing the urban planning data of Dazhou over the years,referring to the latest urban master planning and land use planning results,this paper analyzes the urban spatial expansion of Dazhou.The main research conclusions are as follows:(1)From 2005 to 2015,the urban spatial expansion speed,dynamic degree and intensity changed significantly comparing with 1995 to 2005.The spatial expansion of Dazhou mainly occurred in South,South-southwest,South-southeast and so on.Compared with the previous period,the difference of expansion in each orientation of the latter period is significant,and the expansion speed of the city in the latter period is rapid relatively.At the latter period,the city is in the period of accelerated development,and the type of urban expansion is always shown as the extensive type.The urban expansion model is also reflected in the outward expansion mode along the arterial roads.(2)From the analysis of the basic terrain factors,it can be seen that in the period of 1995 to 2015,the expansion speed and intensity of the urban built-up areas in Dazhou are mainly affected by the roughness of the earth surface,and the elevation,slope and the topographic fluctuation also have a certain influence on it.However,the particularity of aspect,the change of urban expansion has little effect on it.In addition,the change of the dynamic degree is hardly independent of terrain factors.From the analysis of social-economic data,we can see that macroscopical factors,such as land use policies,laws and regulations and urban planning play a role of guiding in the urban spatial expansion;The overall driving effect of social and economic factors on urban spatial expansion,such as the change of regional GDP,the adjustment of industrial structure,the level of urbanization,the investment in social fixed assets,the industrial development and so on;And the construction of urban and surrounding transport infrastructures,urban development zones,the construction and development of large civil airports,they also play an important role in the urban spatial expansion,which can be reflected in all directions of urban spacial expansion.(3)Through combing the urban master plannings of Dazhou over the years,it is found that although the scope of urban planning has changed several times,they are all guided by the plannings.According to the latest texts of "Dazhou Urban Master Planning" and "Dazhou Land Use Master Planning",we can see that the urban spatial expansion of Dazhou is no matter its orientation,speed or scale are basically in line with the planned development of the expected goals.