Expansion of Urumqi urban area and its spatial differentiation

The expanded area and structure of urban lands and landscape features in Urumqi City are analyzed using RS and GIS means based on the MSS image in 1975 and the TM images in 1990,1999 and 2002, as well as other related maps. On which the scale, intensity and spatial differentiation of the expansion of the Urumqi urban area during different periods are lucubrated. The results reveal that urban expansion was rapid during the periods of 1949-1965 and 1975-1990, and that it was stable after the 1990s. The urban expansion pattern was significantly different during different time periods: the urban area was expanded outwards based on old districts in a spanned development pattern during the period of 1949-1965; development was stagnant during the period of 1965-1975; urban expansion developed mainly in old districts in a grouped way during the period of 1975-1990. The trend of urban expansion along the traffic lines was obvious, and the direction of urban expansion was dominated by the south-north zonal expansion and supplemented by east-west axial expansion; urban expansion reached the development stage of "multiple centers and multiple districts" after the 1990s, and urban networks were developed more precisely after this time. The sources for urban expansion were mainly cultivated lands, grasslands and unused lands; during urban expansion, the land area devoted to traffic lines, residential areas, dispersive industrial and mineral areas, and garden plots was rapidly enlarged.