Analyzing The Land Cover Change And Urban Expansion Of Suqian City By Remote Sensing Images

Suqian City is the youngest prefecture-level city in Jiangsu Province. Its GDP is the lowest among 13 cities in Jiangsu Province. Since its establishment as a new prefecture-level city in 1996, the urban areas have been in rapid growth, and obvious land use changes have taken place. With the support of remote sensing and geographic information system, ten scenes of Landsat images captured in on 1992,1999,2003,2009 and 2014 are used to classify land cover. Change transition matrix is used to assess the total land use change on the basis of net change and transfer change. An integrated approach of remote sensing and GIS is used to identify three urban growth types of infilling growth, outlying growth and edge-expansion growth. Urban physical boundaries are extracted on the basis of land use classification. A series of geo-information maps are built to demonstrate and reflect changes of urban expansion at different stages, different directions and different spatial unit. The characteristics of Suqian’s urban sprawl are analyzed through the aspects of spatial distribution, quantitative characteristics, directional characteristics, spatial form evolution and the land cover occupied by urban area.Based on the detailed studies, some conclusions are drawn:(1) The agricultural landscape and forest-lawn landscape are always the dominant land cover categories. The urban landscape becames more than the water landscape for the first time in 2014.The other landscape is the lowest part all the time. During the period between 1992 and 2014, net change of the agricultural landscape and forest-lawn landscape is the largest.(2) During the period of 1992-2014, the proportion of infilling growth and edge-expansion growth increased while the proportion of outlying-type growth decreased.(3) Constrained by the Luoma Lake in the north and Zhangshan Forest in the northeast, urban area of Suqian could only expand to the south. Sucheng district expanded to the fan-shaped area formed by the west and the Great Canal. Suyu district expanded along the Grand Canal and outward. Northern Suqian National Economic and Technological Development Area, the Yanghe River Newtown, Lakeside New City had been planned as key development area.