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]).
In this way, deviation from unit scale can be minimized within a region of interest that lies largely between the two standard parallels.
[2] Pilots use aeronautical charts based on LCC because a straight line drawn on a Lambert conformal conic projection approximates a great-circle route between endpoints for typical flight distances.
[3] The European Environment Agency[4] and the INSPIRE specification for coordinate systems [5] recommends using this projection (also named ETRS89-LCC) for conformal pan-European mapping at scales smaller or equal to 1:500,000.
The National Spatial Framework for India uses Datum WGS84 with a LCC projection and is a recommended NNRMS standard.
The Lambert projection is relatively easy to use: conversions from geodetic (latitude/longitude) to State Plane Grid coordinates involve trigonometric equations that are fairly straightforward and which can be solved on most scientific calculators, especially programmable models.