Using remote sensing and GIS to analyze land use/cover change and urban expansion in Xining City of Qinghai province, China

Four dates Landsat MSS, TM and ETM+ images together with historical topographic maps, land use maps were used to analyze and quantify the temporal dynamics and spatial pattern of land use/cover changes and identify the urban expansion in Xining city, northwest China. The results indicated that from 1977 to 2007, the areas of cultivated land, grassland and unused land decreased by 3.31%, 1.1% and 0.19%, respectively; in contrast, forest land, urban/built-up land increased by 3.8% and 0.75%, respectively. The significant change in land use occurred mainly during the period of 2000 and 2007. Urban area of Xining City had been expanded by 29.25ha over the entire study period, while 64.82% of an increase occurred during the seven-year period from 2000 to 2007. The conversion of cultivated land to forest land, to grassland for ecological protection and urban expansion at the expense of cultivated land were the main land use change.