The Mercator projection is a cylindrical map projection presented by the Flemish geographer and cartographer Gerardus Mercator, in 1569. It became the standard map projection for nautical purposes because of its ability to represent lines of constant true bearing or true course, known as rhumb lines, as straight line segments.

The Gall-Peters projection is one specialization of a configurable equal-area map projection known as the equal-area cylindric or cylindrical equal-area projection. The Gall-Peters achieved considerable notoriety in the late 20th century as the centerpiece of a controversy surrounding the political implications of map design.