two-point azimuthal

doubly azimuthal

orthodromic

Close

McCaw

Immler

Parameters: Anchor point 1, Anchor point 2

Classifications

azimuthal

Graticule

Meridians: Straight lines.
Parallels: Equator is straight. Other parallels are ellipses, parabolas, or hyperbolas.
Poles: Points (if shown).
Symmetry: Normally none.

Aspects

Typically oblique.

Limiting forms

If the two central points are identical, the Gnomonic projection results.

Scale

Varies considerably. Projection should not be used for measuring distance.

Distortion

Direction is correct to all other points from two central points at which there is no distortion.

Other features

Great circles are shown as straight lines. This projection can be obtained by compressing a Gnomonic projection in the direction parallel to the line joining the two central points.

Usage

Could be used to locate a ship at sea, for example, if the exact location of two radio transmitters and the direction from the ship to the transmitters are known.

Similar projections

Gnomonic, which can be compressed as described above to produce the Two-Point azimuthal projection.

Origin

Presented by Hans Maurer (1868-1945) of Germany in 1914 and Charles F. Close (1865-1952) of England independently in 1922.

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.