A common modern projection is the Robinson projection first published in1974 in National Geographic. No flatprojection is totally satisfactory. There are many otherprojections, each designed to reduce distortions in either area, compassdirection, or distance.
The compass direction between twopoints on a Mercator projection is the same as the compass direction betweenthe points on the sphere. The Mercator projectiondoes have one valuable property very useful for navigators. Meridians, as in acylindrical projection, are also improperly displayed as parallel verticallines. It does not preserve relativeareas northern lands like Russia, Greenland, Canada, or Alaska, which appear larger than they reallyare. TheMercator projection produces less distortion at high latitudes. The cylinder is cutvertically and then unrolled. When the surface of this expanding sphere touches the cylinder itsticks. To makethe Mercator projection the cartographer imagines a spherical earth expanding ata constant rate inside the cylinder. Parallels areparallel, but all meridians are also parallel they never meet at the poles.Īnother projection first made by Mercator, a Flemishcartographer about 1560 AD, is another kind of cylindrical projection. The cylindrical projection does not preserve area, norcompass direction. Antarctica hasan infinite area in a cylindrical projection. Areas at highparallels, Russia, Canada, Alaska or Greenland appear much larger than theyreally are. The cylindrical projection is accurate around equatorialregions but it has many disadvantages in polar areas. Polar regions are cut off because they are too far from the equator. The cylinder is unrolled to make thecylindrical projection of the earth. The shadows ofthe parallels and meridians trace the projection on the cylinder. The map-maker imagines the earth is atransparent sphere inside a cylinder with a light at the center of thetransparent sphere. A common wayis to project the sphere of the earth onto a cylinder. There are many mathematical projections of the sphereonto a flat surface. Making a flat map of a sphere must introduce somedistortion. Aristotle's discovery that the earth was a spherepresented problems for later cartographers.
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