The Process and Pattern of Urban Construction Land Expansion in Xuzhou

The expansion of urban construction land,which reflects the urbanization,the spatial process and the characteristics of city development directly,is the most remarkable characteristics of a city in space.Based on maps of urban land use status in 1979,1994,2003,2008 of Xuzhou,the urban construction land information including residential land,industrial land,and commercial and public service land is extracted.Using the method of grid analysis,the spatial and temporal pattern of the urban construction land expansion is analyzed in Xuzhou during the period of transformational development in 1979-2008.The results are showed as follows: 1) The structure of the urban construction land is constantly optimized.During each period of the sustainable expansion of urban construction land,the residential land achieves the sustainable and rapid development,whose growth area and intensity are the highest,in contrast,the industrial land growth is stead,for being controlled, its growth area and intensity is lower.The commercial and public service land growth is inferior,whose growth area and intensity is the lowest.2) The inverse expansion of industrial and residential land is distinctive. As to the structure of expansion types,the inverse expansion of industrial land is the most outstanding, whose inverse expansion is promoted from center to edge of the urban.With the rapid extension of the residential land,its inverse expansion is developed gradually from urban center to middle zone of the urban.All of these also induce that the spatial distribution of urban construction land is optimized.3) Expansion processes of the three types of urban construction land are very quickly and their expansion forms are different.The industrial land constantly expands in form of sheet shape in city's periphery region,then of radial shape alone traffic axis zone and of progressive sheet shape in city periphery region,which shows that the characteristic of aggregating in economic development zone of city periphery region is especially distinctive.The residential land expands rapidly along traffic axis zone,filling in the empty blocks,expanding along axis zone progressively, whose spatial expansion is relative dispersed.The commercial and public service land has been developed more rapidly since 1994,and discrete expansion has been dominating and service industry cluster district has not been formed.And 4) the transition industrial and mining cities are in the period of industrial structure quick adjustment and service function of regional central city rapid enhancement,economy transition and adjustment of industrial structure are the leading forces of the urban construction land expansion,and the transportation is a strong traction force,and city planning is an important regulation force.