Natural Earth Projection – Code
The Natural Earth projection is free for everyone to use. Click here to download resources for implementing it in your software. The download includes:

NaturalEarth.java – the forward and inverse projection formulas in Java.

NaturalEarth.js – the forward and inverse projection formulas in a JavaScript file

PJ_natearth.c – the forward and inverse projection formulas in C for the PROJ.4 library.

Reference_coordinates.rtf – reference points (lon, lat, X, Y) for verifying your implementation.
The Natural Earth projection is now included in the PROJ.4 cartographic projections library.

Do you have questions? Please contact us.