User:Peter Mercator/Draft for Mercator
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In 1569, the Flemish geographer and cartographer Gerardus Mercator produced a map upon which sailing courses at a constant bearing ( [[rhumb line]rhumb lines] were represented by straight lines intersecting vertical meridians at the same angle. This representation of the spherical Earth on the plane is now termed the Mercator projection. The preservation of angle, termed conformality, is obtained by adjusting the equally spaced parallels of a plane chart (Equirectangular projection to maintain the equality of horizontal and vertical scales. Since all parallel circles have the same length on the chart, the horizontal (or parallel) scale increases with latitude and therefore the vertical (or meridian) scale must also increase with latitude; this leads to the distortion at high latitudes which makes the projection unsuitable for a world map. The projection remains the standard for nautical charts and it is also used for accurate mapping at equatorial latitudes where the distortion is minimal. The original Mercator projection is just one member of the Mercator family of conformal cylindric map projections, the most important being the Transverse Mercator projection which is used for accurate large scale mapping in many countries.