Lambert conformal conic projection

Lambert conformal conic projection with standard parallels at 20°N and 50°N. Projection extends toward infinity southward and so has been cut off at 30°S.
The Lambert conformal conic projection with standard parallels at 15°N and 45°N, with Tissot's indicatrix of deformation.
Aeronautical chart on Lambert conformal conic projection with standard parallels at 33°N and 45°N.

A Lambert conformal conic projection (LCC) is a conic map projection used for aeronautical charts, portions of the State Plane Coordinate System, and many national and regional mapping systems. It is one of seven projections introduced by Johann Heinrich Lambert in his 1772 publication Anmerkungen und Zusätze zur Entwerfung der Land- und Himmelscharten (Notes and Comments on the Composition of Terrestrial and Celestial Maps[1]).

Conceptually, the projection conformally maps the surface of the Earth to a cone. The cone is unrolled, and the parallel that was touching the sphere is assigned unit scale. That parallel is called the standard parallel.

By scaling the resulting map, two parallels can be assigned unit scale, with scale decreasing between the two parallels and increasing outside them. This gives the map two standard parallels. In this way, deviation from unit scale can be minimized within a region of interest that lies largely between the two standard parallels. Unlike other conic projections, no true secant form of the projection exists because using a secant cone does not yield the same scale along both standard parallels.[2]

  1. ^ Lambert, Johann Heinrich (1772). Tobler, Waldo (ed.). Notes and Comments on the Composition of Terrestrial and Celestial Maps (Translated and Introduced by W. R. Tobler, 1972). ESRI Press. ISBN 978-1-58948-281-4. Archived from the original on 2014-07-14. Retrieved 2014-07-13.
  2. ^ "CMAPF FAQ". NOAA. Archived from the original on 2012-04-15. Retrieved 2011-12-28.