Mercator

type of map projection, 1660s, invented by Flemish geographer Gerhard Kremer (1512-1594), who Latinized his surname, which means "dealer, tradesman," as Mercator (see merchant). He first used this type of map projection in 1568. Its great distortions in the northern and southern regions renders it unsuitable for land maps, but as on it a constant compass bearing always is represented by a straight line, it is useful for sea maps.