Five projections
No map tells the truth about everything; you only choose where it lies. Each of these five stands for a family, and the table below is their distortion curves - computed from the projections this site actually runs, not transcribed.
| Projection | Latitude | 0° | 30° | 45° | 60° | 72° | 84° |
|---|---|---|---|---|---|---|---|
| Equirectangular | Area distortion | 1.00 | 1.15 | 1.41 | 2.00 | 3.24 | 9.57 |
| Shape distortion | 1.00 | 1.15 | 1.41 | 2.00 | 3.24 | 9.57 | |
| Mercator | Area distortion | 1.00 | 1.33 | 2.00 | 4.00 | 10.5 | 91.5 |
| Shape distortion | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | |
| Natural Earth | Area distortion | 1.00 | 1.11 | 1.26 | 1.49 | 1.97 | 3.47 |
| Shape distortion | 1.16 | 1.05 | 1.12 | 1.55 | 2.51 | 9.24 | |
| Equal Earth | Area distortion | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Shape distortion | 1.35 | 1.15 | 1.09 | 1.69 | 3.43 | 24.6 | |
| Gall-Peters | Area distortion | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Shape distortion | 2.00 | 1.50 | 1.00 | 2.00 | 5.24 | 45.8 |
Equirectangular
The naive one: plot longitude as x and latitude as y. Area and shape both distort as sec(latitude), exactly half the exponent of Mercator's.
Mercator
Conformal: shape survives at every point, and area pays for it, growing as sec squared of latitude - already 91 times over at 84 north.
Natural Earth
A compromise: a little area distortion and a little shape distortion, neither severe. It promises to conserve nothing, which is what a compromise is.
Equal Earth
A modern equal-area projection. Area is conserved exactly everywhere, so the multiplier reads 1.00x wherever you drag. The whole cost lands on shape, about 25 times at high latitude.
Gall-Peters
Cylindrical equal-area at the 45-degree standard parallel. Area is conserved exactly here too, but the shape cost is harsher than Equal Earth's: about 46 times at 84 north.