AuthaGraph projection
An approximately equal-area world map projection invented in 2009.
The AuthaGraph projection, developed in 2009 by Japanese architect Hajime Narukawa, is a world map that roughly preserves area. It is a polyhedral projection: the sphere is split into 96 equal triangles, these are transferred onto a tetrahedron without changing their areas, and then the tetrahedron is unfolded into a rectangle. This approach, inspired by the Dymaxion map, lessens the distortion in the size and shape of every continent and ocean. Unlike the Mercator projection, it does not exaggerate high-latitude landmasses, and it can show Antarctica completely and accurately. The same method can also produce triangular world maps. The name combines "authalic" and "graph."
Although the construction ensures that each of the 96 triangular regions has the correct area, the projection is not truly equal-area because it does not control area at very small scales or within those individual regions.
The AuthaGraph map can be tiled in any direction with no visible seams. This tiling allows new maps with triangular, rectangular, or parallelogram outlines to be framed, with any region placed at the center. This tessellation can also show temporal themes, such as a satellite's continuous path around the Earth over time.
In 2011, the Japanese National Museum of Emerging Science and Innovation (Miraikan) adopted the AuthaGraph as its official mapping tool. In October 2016, it received the Good Design Grand Award from the Japan Institute of Design Promotion.
- year_invented
- 2009
Lore & Background
The AuthaGraph projection was invented by Japanese architect Hajime Narukawa in 2009. The construction method equally divides a spherical surface into 96 triangles, transfers it to a tetrahedron while maintaining area proportions, and unfolds it as a rectangle. The name is derived from 'authalic' and 'graph'. The projection does not have some major distortions of the Mercator projection, such as the expansion of countries in far northern latitudes, and allows Antarctica to be displayed accurately and in whole.
Reader's Guide
The AuthaGraph projection is significant as an approximately equal-area world map that reduces distortion of sizes and shapes of continents and oceans, inspired by the Dymaxion map. It can be tiled in any direction without visible seams, allowing new world maps with triangular, rectangular, or parallelogram outlines to be framed with various regions at center. This tessellation enables depicting temporal themes, such as a satellite's long-term movement around the Earth in a continuous line. In 2011, it was selected by the Japanese National Museum of Emerging Science and Innovation (Miraikan) as its official mapping tool. In October 2016, it won the 2016 Good Design Grand Award from the Japan Institute of Design Promotion. On April 16, 2024, Nebraska Governor Jim Pillen signed a law requiring public schools to use only maps based on the Gall–Peters projection or the AuthaGraph projection beginning in the 2024–2025 school year. The projection does not qualify as equal-area because the method does not control area at infinitesimal scales or even within the 96 regions.
Did You Know?
- The AuthaGraph projection is made by equally dividing a spherical surface into 96 triangles and transferring it to a tetrahedron.
- The projection allows Antarctica to be displayed accurately and in whole.
- In 2011, it was selected by the Japanese National Museum of Emerging Science and Innovation (Miraikan) as its official mapping tool.
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