Density equalized map projections: a method for analysing clustering around a fixed point.
Density equalized map projections: a method for analysing clustering around a fixed point.
复制标题
密度均衡地图投影：一种分析固定点周围聚类的方法。
作者：
J. Schulman;S. Selvin;D. Merrill
由于研究区域人口密度的变化，地缘政治地图上绘制的案例给解释和分析带来了困难。密度均衡地图投影（DEMP）通过将地图面积转换为与人口成比例的方式，消除了常住人口分布的干扰影响。本文讨论了一种变换算法及其属性，并开发了统计方法来检测 DEMP 上绘制的数据围绕固定点的案例聚类。我们建议使用两种数值方法，其中精确解过于复杂或不存在。最后，我们使用科罗拉多州丹佛县和杰斐逊县的数据来说明这些方法，以调查肺癌和白血病的发病模式是否与洛基弗拉茨核电站的钚暴露有关。
Cases plotted on a geopolitical map entail difficulties in interpretation and analysis because of variable population density in the study area. Density equalized map projections (DEMPs) eliminate the distribution of the resident population as an interfering influence by transforming map area to be proportional to population. This paper discusses a transformation algorithm, its properties, and develops statistical methods to detect clustering of cases around a fixed point for data plotted on DEMPs. We suggest two numeric methods where exact solutions are too complicated or do not exist. Finally, we illustrate these methods using data from Denver and Jefferson counties in Colorado to investigate whether lung cancer and leukaemia incidence patterns are associated with plutonium exposure from the Rocky Flats plant site.