The urban expansion trends in the city of Nanjing based on RS and GIS

Abstract

With the acceleration of the Chinese urbanization, the problems between social economy and environment are increasingly serious, and the contradiction between men and land is even more evident. Therefore, how will the urban land growth in cities tend to change? How can we use urban land in an appropriate way? These have become hot topics among many scientific fields. In this paper, we take Nanjing city as an example, using remote sensing and GIS technology to reveal the spatial-temporal dynamics of urban expansion. According to the specific development stages of Nanjing, we classify the whole period into two phases which are 1988-1997, and 1997-2001, and use TM remote sensing images for the years 1988, 1997, 2001 as the basic data sources. In order to obtain the dynamic characteristics of urban land use, we divide the land use type into three types, which are urban land, watershed and green lands through Supervised Classification method. In this study, we use annual changing rate and the urban land expansion index to understand the urban expansion of each region in Nanjing city. Finally, we provide some suggestions to keep the urban land sustainable.