Land Use Change And Urban Expansion Research In Tianjin

Tianjin is the economic center in Bohai Rim, and the biggest Coastal City in Noth China. There have benn many huge changes of land use status with the rapid development of society and economy in Tianjin. So this paper researches land use change and the urban expansion, taking the new coastal region and the central city containd the 6 areas in intracity and 4 areas in around-city in Tianjin as study area. Three phrases of ETM/TM remote sensing images of 1999,2003 and 2007 are used to extract the information of land-use by using the technologies RS and GIS, obtaining the change information of land-use structure in 8 years in this study area by introducing the land use transition matrixes. The range of urban entities of 1999,2003 and 2007 are defined by introducing the land use degree comprehensive index based on the land-use classification. The urban expansion of the new coastal region and the central city is analied separately by spatial distribution, quantitative characteristics, direction characteristics, spatial morphological evolution and the land source for expansion. The results are as follows:(1) The land use change in Tianjin between 1999 and 2007 presents the rule in the course of urbanization, that the urban expansion is realized by occupied farmland. The metastasis status of the land-use type is that the farmland changed into urban land and salt field, the urban land changed from the framlan and salt field, and the salt field changed from the farmland.(2) The urban expansion has the trendence that the city hinterland is developed by the development of coastal and inland area. The expansion type of the central city in Tianjin has changed from fast-propagating in 1999-2003 to rapidly propagating in 2003-2007, and the expansion type of the new coastal region in Tianjin has changed from medium speed propagating in 1999-2003 to fast-propagating in 2003-2007. And the space form of the urban is discrete. The farmland and urban land are the mainly source of the urban expansion, especially the farmland.