Land cover changes in the rural-urban interaction of Xi’an region using Landsat TM/ETM data

LandsatETM /TM data and an artificialneuralnetwork (ANN)were applied to analyse the expansion ofthe city ofXi’an and land use/coverchange ofits surrounding area between 2000 and 2003.Supervised classification and normalized difference barren index (NDBI)were used respectively to retrieve its urban boundary.Results showed thatthe urban area increased by an annual rate of 12.3% ,with area expansion from 253.37 km2 in 2000 to 358.60 km2 in 2003.Large areasoffarmland in the north and southwestwere converted into urban construction land.The land use/coverchangesof Xi’an were mainly caused by fast development of urban economy, population immigration from countryside,greatdevelopmentofinfrastructure such as transportation,and huge demands for urban market.In addition,affected by the governmentpolicy of "returning farmland to woodland",some farmland wasconverted into economicwoodland,such asChinesegoosebeery garden,vineyard etc.