Before revision: Definition The natural Earth is defined by the following formulas: , where x ] , y are the Cartesian coordinates; λ is the longitude from the central meridian ; φ is the latitude ; l(φ) is the length of the parallel at latitude φ; d(φ) is the distance of the parallel from the equator at latitude φ. l(φ) and d(φ) are given as polynomials: In the original definition of the projection, planar coordinates were lineally interpolated from a table of 19 latitudes and then multiplied by other factors.
After revision: Definition The natural Earth is defined b1.4224∈-2.7354, 2.7354and y∈-1.4224∈-π, πin radians∈-π/2, π/2in radians the following formulas: , where x ] , y are the Cartesian coordinates; λ is the longitude from the central meridian ; φ is the latitude ; l(φ) is the length of the parallel at latitude φ; d(φ) is the distance of the parallel from the equator at latitude φ. l(φ) and d(φ) are given as polynomials: In the original definition of the projection, planar coordinates were lineally interpolated from a table of 19 latitudes and then multiplied by other factors.