Hammer retroazimuthal projection
The Hammer retroazimuthal projection is a modified azimuthal proposed by Ernst Hermann Heinrich Hammer in 1910. As a retroazimuthal projection, azimuths (directions) are correct from any point to the designated center point. In whole-world presentation, the back and front hemispheres overlap, making the projection a non-injective function. Given a radius R for the projecting globe, the projection is defined as:
The latitude and longitude of the point to be plotted are φ and λ respectively, and the center point to which all azimuths are to be correct is given as φ1 and λ0.
- Snyder, John P. (1993). Flattening the Earth: Two Thousand Years of Map Projections. Chicago: University of Chicago Press. pp. 228–229. ISBN 0-226-76747-7. Retrieved 2011-11-14.
- Description of Hammer Retroazimuthal front hemisphere.
- Description of Hammer Retroazimuthal back hemisphere.