The Littrow projection is a

map projection In cartography, map projection is the term used to describe a broad set of transformations employed to represent the two-dimensional curved surface of a globe on a plane. In a map projection, coordinates, often expressed as latitude and longit ...

developed by Joseph Johann von Littrow in 1833. It is the only conformal, retroazimuthal map projection. As a retroazimuthal projection, the Littrow shows directions, or azimuths, correctly from any point to the center of the map. Patrick Weir of the

British Merchant Navy The Merchant Navy is the maritime register of the United Kingdom and comprises the seagoing commercial interests of UK-registered ships and their crews. Merchant Navy vessels fly the Red Ensign and are regulated by the Maritime and Coastguard ...

independently reinvented the projection in 1890, after which it began to see more frequent use as recognition of its retroazimuthal property spread. Maps based on the Littrow projection are sometimes referred to as Weir Azimuth diagrams. The projection transforms from latitude ''φ'' and longitude ''λ'' to map coordinates ''x'' and ''y'' via the following equations: :

\begin x &= R \frac  \\
y &= R \cos \left(\lambda - \lambda_0\right) \tan \varphi \end

where ''R'' is the radius of the globe to be projected and ''λ''₀ is the longitude desired for the center point.

References

External links

A Gallery of Map Projections - Azimuthals & RelatedLittrow map
{{Map projections Map projections Conformal projections

See also

References

External links