城市化过程中地形因素对城市空间结构演变的影响——以乌鲁木齐市为例

利用起伏度指数与分布比例指数模型,将地形与城市土地利用类型有机地结合在一起,探讨了地形对乌鲁木齐城市空间结构发展的影响.研究结果表明:两个模型多年相关数据的变化能反映城市空间结构的演变过程.居住用地的增长区从起伏度指数为7～8的地形空间上逐渐开始向起伏较高地形发展.其分布在起伏度指数上的区间扩大了9个单位.由于经济的快速发展,生产建设用地始终在不断地扩大,并表现出工业用地向外扩张和商业用地向内收缩两个变化过程.扩张的方向指向低地形地区,收缩则向金融商业中心.农用地面积始终在减少,并趋向消失,且起伏度低的地区减少得快,而高地形区减少得慢.未利用地分布区域向高地形空间退缩,市区内的未利用地通常被开发为绿地或公园.各种土地利用类型在起伏度指数梯度上分布的整体变化反映出大地形特征仍然是城市空间结构的发展框架.

Influences of Topographic Factors on Change of Urban Spatial Structure in the Process of Urbanization:A Case Study of Urumqi City

This paper analyzed the influence of topographic factors on urban spatial structure in Urumqi using fluctuation index and distribution proportion index based on land use,economic and terrain data combining with GIS.The result indicated that the evolution of urban spatial structure can be reflected by study on the distribution characteristics of land use type along terrain gradient.The growing zone of residential land expanded gradually to undulating terrain from the space that fluctuation index was 7 to 8,so its distributing has extended 9 units.With the fast economic development,the sprawling build-up land underwent two phases of expanding towards low terrain and shrink to financial center.Cropland reduced all the time and tended to disappear.While the reducing speed of cropland was relatively faster for region with low fluctuation index,it is low for wavy terrain.Unused lands shrinked towards high topographical district and they were usually developed into green land or park.The general change of various land types along terrain gradient reflected that the terrain characteristics frame the urban spatial pattern.