Homolosine

Homolosine, commonly referred to as Goode’s Homolosine projection, is an equal-area, composite map projection devised by American cartographer John Paul Goode and introduced in 1923. It is designed to preserve the relative areas of geographic regions while reducing distortion of landmasses by interrupting the map.

Construction and characteristics: The projection combines two different projections. In the mid-latitudes, it uses the sinusoidal projection to achieve approximate area fidelity, while in the polar regions it employs the Mollweide projection. The globe is divided into several interrupted zones, which breaks ocean areas apart to prevent the distortion that would occur if a single continuous projection were used for the entire world. The result is a world map composed of several landmasses arranged in lobes with gaps running through the oceans.

Strengths and limitations: The Homolosine has strong area preservation for continents and true-size relationships across large regions, making it valuable for educational visualization of spatial extent and comparison of land areas. However, the interruptions mean the map is not continuous, making navigation, distance measurement, and global route planning impractical. Coastlines and shapes can appear distorted near the interruption lines, and oceans are represented as broken rather than continuous expanses.

Usage and legacy: It enjoyed widespread use in 20th-century atlases and educational materials as a visually provocative alternative to uninterrupted maps. Today it remains a reference example of a composite, interruptive projection and is often cited in discussions of map distortion and projection design. Related projections include the Mollweide and sinusoidal projections, from which Goode’s Homolosine draws its methods.