Map Projections:
For a globe to be projected onto a two-dimensional
surface, the plane is usually folded or wrapped into
a three-dimensional shape so it can receive the
projected image. The shape of the plane determines
the resulting type of projection. The most
conventional projections methods are Mercator,
conic, and
gnomonic projections: Mercator
projections wrap the plane into a cylinder, conic
projections wrap the plane into a cone, and
gnomonic projections leave the plane flat.
"There is no one map projection which is better than all the others; a
projection which is good for Asia is not necessarily the best for Africa,
and a different projection is used for a navigation chart than for a
statistical map. Each projection has certain virtues and certain
limitations." - Raisz, 166.