Map Projection Distortion
Every flat map of the round Earth must distort something — Gauss proved it. This tool draws the globe’s grid under five classic projections (equirectangular, Mercator, Mollweide, orthographic and stereographic) and overlays Tissot’s indicatrices: small circles on the globe that the map stretches into ellipses. Where the ellipses stay round the projection preserves shape; where they balloon it inflates area — Mercator’s polar explosion and Mollweide’s sheared edges become obvious at a glance.
Runs 100% in your browser — simulations are computed locally on your device.
Read the full guide to this tool
Notes
- Tissot’s indicatrix shows how a tiny circle on the globe is stretched — its shape and size encode the local distortion.
- Conformal maps like Mercator keep the ellipses circular but let their size blow up; equal-area maps like Mollweide fix the area and distort shape.
- No projection is both conformal and equal-area — a consequence of Gauss’s Theorema Egregium.
- Runs 100% in your browser — simulations are computed locally on your device.
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