基于夜间灯光数据的中国城市用地扩展类型

针对目前在城市用地空间扩展类型的划分与识别方面存在的问题,首次提出了基于夜间灯光图像像元灯光强度的时间变化特征对城市用地空间扩展类型进行分类/识别的方法,并应用该方法将中国1992～1998年间的城市用地空间扩展类型分成了3级7大类,进而对这些扩展类型的区域结构、空间分布和开发强度进行了分析,揭示了1992～1998年间中国城市用地空间扩展的一些主要特征.提出以像元为分析对象、并采用多级分类的方法,不仅实现了大尺度上城市用地空间扩展类型的快速识别,而且还在保证分类结果与其他相关研究结果衔接一致的前提下,提供了更为详细且符合实际的城市用地空间扩展信息.

Identification and Characteristics Analysis of Urban Land Expansion Types in China in the 1990s Using DMSP/OLS Data

China has been undergoing widespread urbanization process at unprecedented speed since the 1990s. The urban land expansion is an important aspect of urbanization and has diversified types and characteristics, so the identification of urban land expansion types is thought to be crucial for the study of urbanization and urban development management. In view of the insufficiencies in the previous studies, this paper presented a new method for identifying the urban land expansion types based on the temporal change characteristics of light intensity of each cell obtained from the non-radiance calibrated DMSP/OLS nighttime light data of China in 1992, 1996 and 1998. According to the method, the types of urban land expansion were classified into two categories and seven subtypes as accelerated intensifying type, steadily intensifying type, decelerated intensifying type, unchanging type and unsteady type in the infilling category, and 1996 new expansion type, 1998 new expansion type in the sprawling category. In terms of the classification result, this paper analyzed the characteristics of urban land expansion types in composition structure, spatial distribution and developing intensity further, in which some meaningful conclusions were drawn. The new method presented in this paper seems to be useful because it can not only identify the types of urban land expansion on large scale rapidly and simply, but also provide more detailed and realistic information on urban land expansion on the premise of ensuring the comparability of classification result with other researches.