Winkel’s Tripel was formulated in 1921 by Oswald Winkel of Germany. It is a combined projection that is the arithmetic mean of Plate Carrée and Aitoff’s projection (Maling, 1992).
Neither conformal nor equal-area
Central meridian is straight. Other meridians are curved and are equally spaced along Equator, and concave toward central meridian.
Equidistant spacing of parallels. Equator and poles are straight. Other parallels are curved and concave toward the nearest pole.
Symmetry is maintained along central meridian or Equator.
Scale is true along central meridian and constant along Equator.
Winkel’s Tripel Projection
Source: Snyder and Voxland, 1989