All equal-area maps have their best application as statistical maps, but they are also useful as general reference maps. Their greatest weakness is their distortion of shapes. This can be somewhat alleviated by interruption; but this has drawbacks also, since relationships across a split on the map are lost.
Lambert’s Azimuthal Equal-Area projection not only has equal-area but also true bearing from its center. It presents good shapes within a hemisphere; however, a complete world map becomes severely distorted.
Bonne’s Equal-Area is a conic projection used almost exclusively to portray small areas of the world that have long, narrow shapes extending north-south. Other projections are better suited to east-west expanses.
The Sinusoidal projection is one of the earliest equal-area projections developed. It utilizes horizontal lines, equally spaced in proportion to the true distances between latitudes. These latitude lines are then equally divided into the true proportional distance between meridian lines. The result gives a true area map that presents fairly good shapes up to the edges of the projection. Interruption can improve further on these shapes.
