Heatmap is a common geovisualization method that interpolates and visualizes a set of point observations on a map surface. Most of online web mapping libraries implement a one-pass heatmap algorithm using HTML5 canvas or WebGL for efficient heatmap generation. However, such implementation applies additive operations that accumulate the rendering of point weights on the map surface grid, making it inappropriate for visualizations that require the highlighting of both low and high weights. We introduce \textit{hilomap}, an online heatmap algorithm that highlights surface areas where points with both low and high trends are located. An HTML5 Canvas-based reference implementation on OpenLayers is presented and evaluated.

翻译：热映射是一种常见的地理可视化方法,可以对地图表面的一组点观测进行内插和可视化。大多数在线网络制图图书馆都使用HTML5帆布或WebGL进行一次性热映射算法,以高效热映射生成。然而,这种实施采用了添加操作,在地图表面网格上积累点重力,使光标不适合需要突出低重和高重的可视化。我们引入了\ textit{hilomap},这是一种在线热映算法,以突出显示低低低和高趋势的地表面积。展示和评估了基于HTMLA的OpenLayers参考实施情况。