Mercator is used for navigation or maps of equatorial regions. Any straight line between two points is a true line of constant direction, but not usually the shortest distance between the two points. Distances are true only along the equator, but are reasonably correct within 15° either side. Areas and shapes of large areas are distorted. Distortion increases away from the equator and is extreme in polar regions (Greenland appears larger than Africa but is actually 14 times smaller). Parallels and meridians are straight lines which meet at right angles. Meridians are equally spaced but parallels are stretched towards the poles. Poles are not shown.
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