The original Natural Earth projection defines the length and spacing of parallels in a tabular form for every five degrees of increased latitude. To project all intermediate values, the piece-wise cubic spline interpolation is used.

This graduation thesis introduced alternative polynomial equations that are simpler to compute. The polynomial expression also smoothed the rounded corners where the meridians meet the horizontal pole lines, a distinguishing mark of the Natural Earth projection.

•  Page
•  Map
•  Tool