Directory of Map Projections

What is a projection?

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Hammer retroazimuthal front hemisphere

Parameters: Latitude of origin




Meridians: Central meridian is straight. Other meridians are curved.
Parallels: Curved.
Poles: Curved lines.
Symmetry: About the central meridian.


Extreme distortion of area and shape.

Other features

The direction from any point to the center of the map is the angle that a straight line connecting the two points makes with a vertical line. This feature is the basis of the term “retroazimuthal.” Scimitar-shaped boundary. Considerable overlapping when the entire sphere is shown.


To determine the direction of a central point from a given location.

Similar projections

Craig Retroazimuthal has straight, equally spaced meridians.


Presented by H.H. Ernst von Hammer (1858–1925) of Germany in 1910. Independently presented by Edward A. Reeves (1862–1945) and Arthur R. Hinks (1874–1945) of England in 1929.

Description adapted from J.P. Snyder and P.M. Voxland, An Album of Map Projections, U.S. Geological Survey Professional Paper 1453. United States Government Printing Office: 1989.