Van der Grinten
This projection is neither conformal nor equal-area, but shows the globe enclosed in a circle. This projection is exclusively used for world maps. The central meridian and Equator are straight lines, with scale true along the equator only.
The "Van der Grinten" projection has the following parameters:
Note: If the spherical radius parameter is set to a value greater than zero, then it will be used as the radius of the sphere. If this parameter is set to a value less than or equal to zero, then the semi-major axis of the ellipsoid will be used as the radius of the sphere.