Online Heatmap Generation with Both High and Low Weights

TL;DR

This paper introduces hilomap, an online heatmap algorithm that effectively visualizes both low and high point weights on maps, addressing limitations of existing methods that only highlight high weights.

Contribution

The paper presents hilomap, a novel online heatmap algorithm capable of highlighting both low and high weights, improving geovisualization of diverse data trends.

Findings

Hilomap effectively visualizes both low and high weights on heatmaps.

The implementation on OpenLayers demonstrates practical applicability.

Evaluation shows improved highlighting of data variations.

Abstract

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.