Natural Earth vs Equal Earth
Natural Earth and Equal Earth, measured item by item. Every figure below is labelled with the projection whose equator it is normalised to.
What each one is
| Property | Natural Earth | Equal Earth |
|---|---|---|
| Family | Compromise pseudocylindrical | Equal-area pseudocylindrical |
| Axis held at 1.00 | Neither | Area |
| Leads with | Area distortion | Shape distortion |
| True-shape parallel | 36.2° | 40.4° |
| Aspect ratio | 1.923 : 1 | 2.055 : 1 |
| Pole drawn as a line | 55% of the equator | 59% 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 | Natural Earth area | Equal Earth area | Natural Earth shape | Equal Earth shape |
|---|---|---|---|---|
| 0° | 1.00 | 1.00 | 1.16 | 1.35 |
| 30° | 1.11 | 1.00 | 1.05 | 1.15 |
| 45° | 1.26 | 1.00 | 1.12 | 1.09 |
| 60° | 1.49 | 1.00 | 1.55 | 1.69 |
| 72° | 1.97 | 1.00 | 2.51 | 3.43 |
| 84° | 3.47 | 1.00 | 9.24 | 24.6 |
What they disagree about most
The objects Natural Earth and Equal 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 Natural Earth multiples are normalised to Natural Earth's equator and the Equal Earth multiples to Equal 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 | Natural Earth area | Equal Earth area | Natural Earth ÷ Equal Earth |
|---|---|---|---|
| Greenland | 2.13 | 1.00 | 2.13 |
| Norway | 1.79 | 1.00 | 1.79 |
| Iceland | 1.64 | 1.00 | 1.64 |
| Finland | 1.62 | 1.00 | 1.62 |
| Sweden | 1.57 | 1.00 | 1.57 |
| Russia | 1.55 | 1.00 | 1.55 |
| Canada | 1.53 | 1.00 | 1.53 |
| Estonia | 1.46 | 1.00 | 1.46 |
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
The equal-area one is exact about area. The compromise one is not - it trades a little area error for a better-looking outline, and usually trades well.
So the choice is about what the map has to carry. If sizes are going to be read off it, or if it is there to support a claim about size, use the equal-area one: its area axis is 1.00 at every latitude and the reader has to trust nobody. If it is a reference base map, a wall map or an illustration, the compromise one usually looks better - and its area error belongs on the page in writing.
The problem with a compromise projection is not that it is inaccurate. It is that it does not announce where it is inaccurate. Every page here prints that number.
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.