"A globe is, of course, the only possible medium for showing all geograpical relationships in true perspective...But globes have a serious drawback:they are limited in scale. A globe which would show a continent on the same scale as most standard maps would have to be two, three, perhaps four meters in diameter."John Noble Wilford from The Mapmakers



Mathematics of Cartography 

Mathematics TopicsProjections 

Round Earth, Flat Map from National Geographic
Make a Map Projection 
Map projectionA function or transformation which relates coordinates of points on a curved surface to coordinates of points on a plane. 

Exercises in Oceanography Great info on projections 
A ProblemIf you cut a cylinder apart lengthwise, you can lay it flat. (Think about a can label). Can you cut apart a sphere and lay it out flat? 

More Great info 
For ExampleThe Mercator Projection Angles are preserved, but distances away from the equator become progressively distorted. (South America is actually nine times as big as Greenland. 

Another ExampleSee how much this changes your perspective! 

Map Projections  More InfoThe Mercator projection is called Conformal A projection is conformal if the angles in the original features are preserved. 

A Gallery of Projections
At The Great Gallery Globe you will find examples of several different projections. Remember, the cartographer chooses the projection which most closely fits the purposes of her map. 


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Copyright 19962004 Cynthia LaniusBack to Math Topics 