Equirectangular vs Natural Earth
Equirectangular and Natural Earth, measured item by item. Every figure below is labelled with the projection whose equator it is normalised to.
What each one is
| Property | Equirectangular | Natural Earth |
|---|---|---|
| Family | Equidistant cylindrical | Compromise pseudocylindrical |
| Axis held at 1.00 | Neither | Neither |
| Leads with | Area distortion | Area distortion |
| True-shape parallel | 0.0° | 36.2° |
| Aspect ratio | 2.000 : 1 | 1.923 : 1 |
| Pole drawn as a line | As long as the equator | 55% of the equator |
The same parallel, under each
Six parallels, two axes. The area columns are normalised to that projection's own equator; the shape columns are the ratio of the Tissot indicatrix's axes at the same point, where 1.00 means the shape there is unchanged. Each projection reads against its own baseline, so the two area figures on a row are not two readings on one axis.
| Latitude | Equirectangular area | Natural Earth area | Equirectangular shape | Natural Earth shape |
|---|---|---|---|---|
| 0° | 1.00 | 1.00 | 1.00 | 1.16 |
| 30° | 1.15 | 1.11 | 1.15 | 1.05 |
| 45° | 1.41 | 1.26 | 1.41 | 1.12 |
| 60° | 2.00 | 1.49 | 2.00 | 1.55 |
| 72° | 3.24 | 1.97 | 3.24 | 2.51 |
| 84° | 9.57 | 3.47 | 9.57 | 9.24 |
What they disagree about most
The objects Equirectangular and Natural Earth treat most differently. The first two columns stand alone: each is the area that object is painted at under that projection, against that projection's own equator. The third is the ratio between them.
Once more, because it matters: the Equirectangular multiples are normalised to Equirectangular's equator and the Natural Earth multiples to Natural Earth's. The two do not share an axis. What the third column exactly means is this - print both maps with equators the same length, and this shape comes out that many times larger on the first than on the second. It is a checkable statement about two pictures, not a physical quantity.
| Object | Equirectangular area | Natural Earth area | Equirectangular ÷ Natural Earth |
|---|---|---|---|
| Greenland | 3.83 | 2.13 | 1.79 |
| Norway | 2.83 | 1.79 | 1.58 |
| Iceland | 2.37 | 1.64 | 1.45 |
| Finland | 2.33 | 1.62 | 1.44 |
| Sweden | 2.19 | 1.57 | 1.40 |
| Russia | 2.14 | 1.55 | 1.38 |
| Canada | 2.12 | 1.53 | 1.38 |
| North America | 1.90 | 1.43 | 1.33 |
Area multiples are integrated over the whole polygon as drawn, not estimated from a centroid latitude. Shape ratios are taken at the object's anchor.
Which to use
Neither holds either axis; both pick a position between area and shape. So there is no "which is right" in this pairing, only where each compromise lands.
Read both tables: on which parallel is whose area error smaller, and which stretches the outline less. Those two usually run in opposite directions.
If sizes are going to be read off the page, neither is enough. Use an equal-area projection instead.
See it in the tool
Switching projections in the tool morphs the map between the two - it interpolates projected pixel coordinates, so which places shrink and which swell is visible at a glance. It is the fastest way on this site to understand what separates a pair.