Jigu tool lets you drag countries across projections to reveal map distortions

Jigu is a new interactive web tool designed to make the area distortions of common map projections visible and measurable. It displays Mercator and Equal Earth projections simultaneously on one screen, separated by a moving boundary that lets users watch countries change shape and size in real time. Users can drag a country to a different latitude — for example, pulling Greenland to the equator shrinks its displayed area from over 22 million km² to around 2 million km², closer to its true size. The tool also offers a 3D globe view, where projected area always matches true area, eliminating distortion entirely. Built with D3.js, Jigu uses per-latitude blending and polygon-level distortion measurement to ensure accurate, fold-free rendering across all regions including the poles.