Classifications
Modified azimuthal
Neither conformal nor equal area
Graticule
Meridians: Straight lines
Parallels: Equator is straight. Other parallels are ellipses, parabolas, or hyperbolas.
Poles: Points (if shown)
Symmetry: Normally none
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
Origin
Presented by Hans Maurer (1868-1945) of Germany in 1914 and Charles F. Close (1865-1952) of England independently in 1922
Aspects
Typically oblique
Other names
Doubly Azimuthal
Orthodromic
Close
McCaw Immler
Limiting forms
If the two central points are identical, the Gnomonic projection results.
Similar projections
Gnomonic, which can be compressed as described above to produce the Two-Point Azimuthal projection
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.