Research on Urban Expansion and Drive Mechanism in an Oasis Town of Arid Region—A Case of Zhangye City

In the process of social development,city,as the most frequent focus of regional human activity,evolves constantly with social economy development. Since the reform and opening up,Chinese economy enter into a period of rapid development,urban construction and urbanization has made great achievements and urban regional spatial extension expands continually. In this paper,A western typical oasis city in arid area,Zhangye city as an example,we extracted expansion information of urban construction land-use in Zhangye with artificial visual interpretation and overlay technology,focus on analyzing the urban expansion intensity,shift of the city center,urban morphology,direction of urban expansion as well as the situation of the land occupied by urban expansion during 30 years of different period,and reveal the driving mechanism of urban expansion in Zhangye based on multi-temporal Landsat MSS / TM / ETM data and GIS. The main conclusions are as follows: 1 since the reform and opening up,the urban construction land expands the three times in Zhangye city. The Urban land expansion trend is most obvious after 2000 year,the arable land,residential area and mining land is mainly the occupied land-use type. 2 At present stage,the urban expansion mainly being outgoing extension and internal filling,the space form of the urban is compact,the city center shifted to the northeast,and the northeast,south and west is the mainly expansion direction. 3 The Natural geography condition constrains and guides the urban expansion; the social economy development has a promoting effect; and the government decision making and urban planning determines the scale and spatial pattern of urban expansion. The above research result is very significant to provide scientific development strategy for making Zhangye an oasis city being fit for living,touism,business,etc.