1. What is the Equal Earth Map Projection?
The Equal Earth map projection is an equal-area pseudocylindrical projection created in 2018 by cartographers Bojan Šavrič (Environmental Systems Research Institute / Esri), Bernhard Jenny (Monash University), and Tom Patterson (US National Park Service, retired).
It was published in the peer-reviewed journal International Journal of Geographical Information Science (Vol. 33, Issue 3, pp. 510–529; DOI: 10.1080/13658816.2018.1504949).
Mathematical Definition: On an equal-area (equivalent) projection, the ratio of any projected area on the 2D plane to its real spherical surface area on Earth is strictly constant ($1.0$). Equal Earth achieves this while ensuring parallels of latitude remain straight horizontal lines and meridians curve smoothly to emulate a globe.
2. Forward Equations & Polynomial Coefficients
For spherical latitude $\phi$ and longitude $\lambda$ (relative to central meridian $\lambda_0$):
$x = \frac{2 \sqrt{3} (\lambda - \lambda_0) \cos(\theta)}{3 (A_1 + 3 A_2 \theta^2 + 7 A_3 \theta^6 + 9 A_4 \theta^8)}$
$y = \theta (A_1 + A_2 \theta^2 + A_3 \theta^6 + A_4 \theta^8)$
With the official parametric coefficients:
- $A_1 = 1.340264$
- $A_2 = -0.081106$
- $A_3 = 0.000893$
- $A_4 = 0.003796$
Standard parallels are located at $44^\circ 45'\text{N}$ and $44^\circ 45'\text{S}$, where angular and scale distortion are minimized.
3. Authoritative Geographic Datasets
Our geographic layers and statistical indices are compiled from authoritative international organizations:
- Natural Earth Vector Data (v5.1.2): Used for 1:50m and 1:110m administrative country boundary polygon coordinates. Natural Earth is built by the North American Cartographic Information Society (NACIS).
- United Nations Geospatial Information Section (UN-GIS): Used for international boundary verification and standard naming conventions.
- WGS84 Geodetic Ellipsoid Standard: Surface area measurements are calculated over the World Geodetic System 1984 reference ellipsoid ($a = 6,378,137.0\text{ m}$, $f = 1/298.257223563$) to account for the Earth’s equatorial bulge. Total global land area is benchmarked at $148,940,000\text{ km}^2$ ($57,506,000\text{ mi}^2$).
- UN DESA Population Division (2024 Revision): Demographic estimations for country profiles and continental totals.
4. Treatment of Sovereign States, Dependencies & Disputed Regions
A. Sovereign Nations: 193 UN Member States plus UN Observer States (Vatican City and State of Palestine) are indexed with official ISO 3166-1 alpha-2, alpha-3, and numeric codes.
B. Autonomous Territories & Dependencies: Prominent geographic landmasses that are autonomous territories or dependencies (e.g., Greenland, French Guiana, Puerto Rico, Falkland Islands) are indexed with dedicated profile and comparison capabilities, with clear classification badges indicating territory status.
C. Boundary Disputes: Line representations in our vector map reflect de facto administrative control and standard UN cartographic guidelines. EqualEarthMap.in is an educational platform dedicated to spatial geometry and projection comparison; it does not adjudicate sovereign boundary disputes.
5. Known Cartographic Trade-offs
Per Gauss's Theorema Egregium, no flat map can preserve all properties simultaneously. While Equal Earth achieves 100% proportional surface area preservation:
- Angular Distortion: Away from the standard parallels ($44^\circ 45'$), shapes experience mild pseudocylindrical shearing. For local navigation or engineering surveys, conformal projections (such as UTM or local Lambert Conformal) remain necessary.
- Rhumb Lines: Unlike Mercator, lines of constant compass bearing are curved lines on Equal Earth.
6. Data Review Schedule & Error Reporting
Our datasets undergo bi-annual structural reviews to incorporate official census updates, boundary adjustments, and geodetic refinement.
Next Scheduled Audit: April 2027
If you discover an error, discrepancy, or broken vector polygon, please notify our cartographic team at hi@equalearthmap.in or submit a report via our Contact & Feedback form.