与传统上地图分级的研究重点关注分级统计精度和图面效果不同,本文提出了一种用于表达和传输人口密度空间分布知识的自动化地图分级方法。该方法基于人口密度分布Lorenz曲线,根据知识传递的需要确定制图分级数,通过Lorenz曲线化简的方法确定分级间隔,以更好地表达人口空间分布的规律性知识,增强地图信息的传输效果。试验表明,分为两级时该方法能够自动地得出"胡焕庸线"的基本轮廓,分为多级时能够很好地体现人口空间分布的基本规律和特例知识。
Different from traditional researches which focus on statistics accuracy and representation effects of choropleth map,a new automatic method of determining class intervals in representing knowledge of population distribution is proposed in this paper.Based on population distribution Lorenz curve,the method can determine the number of classes by requirement of knowledge transfer as well as determine the class interval via the Douglas-Peucker simplification method.Experiments of the method demonstrate the potential of representing population distribution patterns and the improvement of map information transfer.During simplification,the two class interval map shows the approximate outline of "Hu line".The population distribution patterns and knowledge of particular cases are easily understood from maps of three or more class intervals.