Mercator's compass

Mercator’s compass refers to the navigational method developed by Gerardus Mercator, which uses a projection of the Earth onto a flat map. It enables sailors to plot straight-line courses, called rhumb lines, that maintain a constant compass bearing. By translating curved surfaces into a flat map while preserving angles, it simplifies navigation over long distances. This technique revolutionized maritime travel, making it easier to chart courses across oceans. Although it distorts distances and sizes near the poles, the Mercator projection remains valuable for navigation, as it allows sailors to follow consistent compass directions on a two-dimensional map.