Mapping the Earth’s curved surface onto a flat, two-dimensional map inherently introduces distortions. Cartographers develop various map projections to manage these distortions, each prioritizing properties like shape, distance, or area. The Goode Homolosine projection offers a distinctive approach to representing the entire world, providing an alternative to common maps that often misrepresent the true sizes of continents and oceans.
What is the Goode Homolosine Projection?
The Goode Homolosine projection is a unique world map projection developed by American geographer John Paul Goode in 1923. It is classified as pseudocylindrical, meaning its meridians curve, and is a composite projection, combining elements from two existing projections. The name “Homolosine” is a blend derived from “homolographic” (another name for the Mollweide projection) and “sinusoidal,” reflecting its dual origin.
The Goode Homolosine projection merges the Sinusoidal projection for equatorial regions and the Mollweide projection for higher latitudes. The Sinusoidal projection is used between approximately 40° North and South latitudes, with the Mollweide projection covering areas closer to the poles. This combination minimizes overall distortion by leveraging the strengths of each component projection in different latitudinal zones, where their scales align seamlessly.
A defining characteristic of the Goode Homolosine projection is its “equal-area” or “equivalent” property. This means every region on the map maintains its proportional size relative to its actual size on Earth. This property is achieved because both the Sinusoidal and Mollweide projections are equal-area. To further reduce distortion, especially for landmasses, the map is typically presented in an “interrupted” form, dividing it into multiple lobes. Interruptions usually occur over the oceans, where continuity is less critical.
Key Uses
The Goode Homolosine projection is primarily used in thematic mapping, especially when accurate representation of land area is important. Its equal-area property makes it an effective tool for visualizing global statistical data, as the relative sizes of geographic features on the map directly correspond to their real-world areas. This allows for clear comparisons of phenomena distributed across the Earth’s surface.
For instance, this projection is frequently employed in environmental mapping. It helps illustrate global patterns such as vegetation zones, climate classifications, or land use changes, providing an accurate spatial context for these distributions. Researchers and analysts often prefer it for studies involving population density, resource allocation, or biodiversity, where understanding the true extent of areas is more important than precise shapes or distances.
Educational institutions and scientific organizations, including the U.S. Geological Survey (USGS), adopt the Goode Homolosine projection for various global datasets. It is used for displaying satellite imagery and global land cover characterization data. The projection’s ability to accurately represent continent sizes makes it a common choice for textbooks and atlases, such as Goode’s Atlas, to provide a realistic view of world geography.
Benefits and Drawbacks
The Goode Homolosine projection offers several practical advantages for specific mapping purposes. Its primary benefit is the preservation of true relative areas, meaning the size of any country or continent on the map accurately reflects its proportion on Earth. This is particularly useful for analyses relying on accurate spatial data, preventing misperception of landmass sizes common with other projections like Mercator. The interrupted nature also minimizes shape distortion across landmasses, especially within individual lobes.
Despite its strengths, the Goode Homolosine projection has notable drawbacks. The interruptions, while beneficial for preserving land area and shape, create discontinuities across the oceans. This fragmentation makes it challenging to visualize oceanic features or measure distances and directions across the breaks. Consequently, the projection is unsuitable for navigation or maps requiring continuous ocean expanses. While shapes are generally better preserved than in some other equal-area projections, some distortion still occurs, particularly near lobe edges or in areas like Greenland and Antarctica.