Hammer

Hammer-Aitoff

Parameters: Parallel curvature 0 << W ≤ 1.0

Classifications

lenticular
equal-area

Graticule

Meridians: Central meridian is a straight line half the length of the equator. Other meridians are complex curves, unequally spaced along the equator and concave toward the central meridian.
Parallels: Equator is straight. Other parallels are complex curves, unequally spaced along the central meridian and concave toward the nearest pole.
Poles: Points.
Symmetry: About the central meridian and the equator.

Aspects

Normal and oblique are both in use.

Scale

Decreases along the central meridian and the equator with distance from the center.

Distortion

Moderate. Less shearing action on the outer meridians near the poles than there is on pseudocylindric projections.

Other features

Elliptical border. An equatorial aspect of one hemisphere of the Lambert azimuthal equal-area projection, on which horizontal coordinates have been doubled and meridians have been given twice their original longitudes.

Usage

Whole-world maps, also in interrupted and condensed forms.

Similar projections

Briesemeister, a modified oblique Hammer.
Eckert-Greifendorff, a further modification of the Lambert azimuthal equal-area projection.

Origin

Presented by H.H. Ernst von Hammer (1858–1925) of Germany in 1892.

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.