Geocart Projections

What is a projection?

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Geocart menu class: Azimuthal
Geocart family: Retroazimuthal


Meridians: Central meridian and meridians 90° away are straight. Others are hyperbolas convex toward the central meridian.
Parallels: Equator is straight. Other parallels are ellipses; the Equator lies along their major axes.
Poles: Not shown
Symmetry: About the central meridian and the Equator


Varies rapidly


Extreme distortion of area

Other features

Cannot show the entire sphere. Shows the correct direction from any point on the map to any point along the central meridian as the angle between a straight line connecting the two points and a vertical straight line parallel to the central meriian.


By the British Navy in the 19th century to determine directions to a central point from other locations


Presented by J.J. Littrow of Austria in 1833

Similar projections

Littrow projection is the transverse aspect of a Lagrange projection having certain parameters.

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.