Spatial pattern and evolution of urban construction land in Xuzhou

Based on maps of urban land use in 1979,1994,2003,2008,1∶50000 topographic map in 1994 of Xuzhou,with reference to the latest national standards of the land-use status classification(GB/T21010-2007),urban construction land was identified into residential land,industrial land,commercial and public service land,a vector database of the urban construction land was established and the 10m×10m grid database was generated by re-sampling in Xuzhou urban area.Then a spatial study on the urban construction land of Xuzhou was carried out in the aspects of distance,orientation and spatial pattern relationship,using the methods of GIS such as circle-layer and fan-shaped analysis based on the vector database,and spatial rhythmic analysis based on the grid database.The results were obtained as follows.(1) The line charts of distance about all the three types of urban construction land had the same process of changing from single-peak to multi-peak;both the crest location and the growth area of industrial and residential land had a trend of developing outward;industrial land replacement was steadily developing from the city center to the outer city;residential land had been decreasing within a scope of 0-5 km from the city centre since 1994;by contrast,the commercial and public service land had not a trend of developing outward and its growth had no continuity.(2) Commercial and public service land developed relatively slowly in each orientation;industrial land expanded steadily to the northeast industrial area and the northwest and south outer city;residential land and commercial and public service land expanded rapidly to the beautiful southeast which was set as the dominant orientation of the city.(3) With the rapid development of the city,the three types of urban construction land formed a relationship of discrete extension,then a relationship of cohesive extension;under the effect of the heavy industry,the commercial and public service land,which developed slowly and served industry to a large degree,and the industrial land displayed a relationship of discrete extension,and the characteristic that the industrial area and residential land separated from each other was relatively distinctive.