The Eckert IV projection is another attempt to moderate the behavior of the equal-area sinusoidal projection.
Again, this is an equal-area projection. Since the shape of this projection occupies more space than an ellipse, as well as a sinusoid, the stretching of continents at the Equator is considerably more noticeable than on the Mollweide.
However, it is a good compromise between projections like the Mollweide on the one hand, and the Equal-Area Cylindrical projection on the other. Although it can be interrupted, being a pseudocylindrical projection, shear is kept low enough with this projection that interruption is usually not required.
As this diagram illustrates,
although the equation is different, the mathematical basis for locating the parallels on this projection is very similar to that used for the Mollweide projection.