Aitoff Projection
Nov 27,2025

GISBox is a one-stop 3D GIS data editing, conversion and publishing platform that supports editing in multiple GIS formats such as OSGB/GEOTIFF/RVT, converting to 3DTiles/Terrain and publishing.

Introduction

Aitoff projection is a specialized map projection method first proposed by the German mathematician David A. Aitoff in 1889. As a compromise projection, it aims to balance distortions in angle, area, and distance, making it suitable for global overview maps. The Aitoff projection is an improvement upon the azimuthal equidistant projection. By horizontally stretching the original hemispherical projection to twice its width, it forms an elliptical map where the width is double the height. This projection is particularly well-suited for displaying regions centered on specific points, such as polar areas or cities, while providing a relatively balanced view of the world.

Projection Basic

The fundamental principle of the Aitoff projection lies in how points on the Earth's surface are mapped onto a plane. First, an azimuthal equidistant projection is used to project the Earth's surface onto a planar disk, ensuring that all great-circle paths from the center point maintain their true directions. This disk is then uniformly stretched horizontally to twice its original diameter, resulting in the final elliptical map. This method not only preserves the directional accuracy of great-circle paths but also attempts to reduce shape and area distortions caused by the projection.

Pros

Moderate overall shape fidelity: As a compromise projection, it offers better visual balance for global outlines compared to projections with extreme distortions (e.g., the high-latitude stretching of the Mercator), making it suitable for overview world maps.
Minimal distortion in central regions: The scale remains true along the equator and the central meridian (typically the 0° meridian), ensuring relatively accurate shapes of continents in the central area (e.g., Africa and Europe).
Symmetrical and clear graticule: Meridians appear as smooth curves converging toward the poles, while parallels are equidistant symmetric curves, facilitating an intuitive understanding of the Earth's spherical form.

Cons

Neither conformal nor equal-area: It does not preserve angles (leading to navigation errors) nor maintain area proportions (e.g., Greenland still appears disproportionately large compared to South America), making it unsuitable for precise measurements.
Significant edge distortion: Stretching and compression intensify at the map edges (particularly the eastern and western extremities and high latitudes), causing shape distortions in regions like the Russian Far East and Alaska.
Severe distortion in high-latitude regions: The poles are stretched into arcs rather than points, resulting in abnormal geometric forms in polar areas (e.g., excessive elongation of Antarctica).
Limited to small-scale use: Due to unacceptable distortion at larger scales, it is only suitable for global or continental overview maps and not for mapping local regions.
Non-rectangular projection boundary: The elliptical shape results in inefficient use of paper or screen space, requiring additional handling of blank areas.

Application Scenario

Due to its elliptical outline and visually balanced overall form, the Aitoff projection is primarily used for non-precise global overview scenarios. Examples include educational materials for intuitively displaying the relative positions of continents and the Earth's curvature, or thematic maps illustrating climate zones or population trends. It is also suitable for artistic map creation and poster design, leveraging its distinctive curved graticule to enhance visual appeal. Additionally, in GIS tools, it serves as a quickly generated global base map for overlaying routes or macro-level data distribution analysis. However, it is essential to emphasize that it is not suitable for navigation, measurement, or other high-precision applications.