Real-time terminator on a Mercator world map
D3.js v7 draws the globe with TopoJSON land; the solar terminator updates with the browser clock. Educational copy explains axial tilt and seasons. All heavy lifting is CDN-delivered—no bundler for the stock demo.
Architecture
| Rendering | SVG or canvas path via D3 geo projections; sun position from astronomical approximations for “now”. |
|---|---|
| Data | World outline from TopoJSON; small payload suitable for caching. |
| Hosting | Static files under /mercator/; works offline after first load if you vendor scripts (currently CDN). |
Design
The visualization prioritizes geographic accuracy of the terminator curve over game-like UI: it’s a science communication piece with readable typography for time/date readouts.