21世纪初期南京城市用地类型与用地强度演变关系

城市三维空间扩展已成为21世纪初期中国城市空间扩展的重要特征。利用南京市2000年和2012年两期三维城市数字重建成果,将地类变化转移矩阵的应用方法进行拓展,研究城市建成区用地类型变化引致的用地强度的演变。主要结论为：① 21世纪以来南京建成区处于高速扩张之中,12年间工业用地增长幅度最大,其增加的来源主要是农用地,其次为住宅用地,农用地和水域面积减少较为明显;② 在城市内部5种主要地类的转化过程中,除住宅用地转为其他建设用地的类型容积率有所降低外,其余转换类型容积率均有明显增长,城市内部用地类型未发生变化的地块,容积率也处在不断的提高中;③ 在城市扩展区各地类的容积率保持在较好的水平,新增住宅、教育和其他建设用地的容积率超过了老城区相应地类的容积率,新建工业用地容积率与老工业用地容积率持平,新建商业用地容积率是老商业用地容积率的65.67%。

The relationship of evolution between urban land use types and intensity in Nanjing since the early 21st century

Three-dimensional urban space expansion has become an important feature of China’s urban spatial expansion since the early 21st century. Based on the three-dimensional digital reconstruction results of Nanjing in 2000 and 2012, this paper expanded the application methods of land use types transfer-matrix to study the evolution of land use intensity caused by the changes of land use types in urban built-up areas. The results consist of three aspects: (1) Nanjing's built-up area has experienced rapid expansion since the early 21st century, and it expanded 50.50 km² per year on average. During the past 12 years, industrial land attained maximal growth with an expansion of 155.34 km², and its main incremental source was agricultural land, followed by residential land. Agricultural land and water area decreased obviously, and the lost agricultural land was transferred mainly to industrial land. (2) The sequence of average plot ratio of five major land use types in built-up areas, which were commercial land, residential land, educational land, industrial land and land for other construction purposes in descending order, did not change from 2000 to 2012, and the average plot ratio of the first four land use types increased by 0.59, 0.48, 0.31 and 0.06, respectively. In the transformation processes of five major land use types in built-up areas, the plot ratio of residential land converted to other construction land decreased, while other conversion types significantly increased. The plot ratio of unchanged land use types also constantly rose. (3) The plot ratios of new residential and educational lands as well as land for other construction purposes exceeded those of the corresponding land types in the old town, suggesting that the plot ratios of land types in the urban expansion area were at a higher level. The plot ratios of new industrial land and old industrial land were unchanged. The plot ratio of new commercial land was 65.67% of that of old commercial land.