人口密度、夜间光数据及MODIS的全球城市分类

摘要

针对因受到城市区域物理结构的物质、文化和社会经济因素的影响,全球范围内大都市区域的人口密度、夜间光和植被覆盖数据的直接对比研究极少的问题,该文利用中低空间分辨率的遥感影像对全球城市进行分类研究.为了能够对城市进行定量研究,有必要将城市简化为基本土地覆盖物的综合体.对选定的25座全球城市从3个方面(人口密度、稳定夜间光强度和植被覆盖指数)进行对比分析,根据其组合特征将全球城市分为5大类型(极高强度、高强度、中强度、低强度、极低强度).研究结果表明,这一方法包含了影响城市分类现状的80％以上的因素,城市特征信息可以精确地描述为人口密度、稳定夜间光强度和植被覆盖指数在二维混合空间上的组合.%Because of the influence of diverse physical,cultural and socioeconomic factors on the physical structure of urban areas,there are few direct comparative analysis between continents and metropolitan regions all over the world.To solve this problem,this paper uses coarse resolution satellite images to study global urban characterization.Urban environments are so heterogeneous.It is necessary to simplify them as combination of basic land cover materials in order to enable quantitative studies.A comparative analysis of three-component features(population density,NDVI,DMSP)for 25 urban areas worldwide provides a physical basis of global urban characterization.The study classifies the urban types into five types(very-low,low-,medium-,high-and very-high-intensity urban types)based on the combination of population density,NDVI and DMSP.The results of this analysis indicate that the characteristics of these cities can be accurately described as linear combinations of population density,DMSP and vegetation end members within a two dimensional mixing space containing over 80％ of variance in the observed data.Global urban characterizations provide a basis of mapping the spatial extent of human settlements using coarse resolution satellite imagery.