Representations of the Earth essays

Representations of the Earth essays The Globe is the best representation of the Earths surface. All distances, areas, and shapers are truly and proportionally represented. Globes do have disadvantages such as their unmanageable shape and very small scale. Because of this, cartographers created maps, or projections of the Earths surface onto a developable surface surface that can be rolled out onto a flat plane. The only possible developmental surfaces for globe projections are the cylinder, the cone, and the plane. These developmental surfaces create three natural projection classes: cylindrical, conic, and azimuthal. A cylindrical projection is as if a cylinder were wrapped around a globe which has a light projecting through it. Once the cylinder is rolled out, it creates a two dimensional rectangular projection of the globe. A conic projection is created when a cone is placed tangent to the globe along any small circle and a light is projected from a point opposite of the cones tip. When rolled out, a conic projection appears relatively triangular. An azimuthal projection occurs when a plane is placed on a single point of a globe and a light is projected from the opposite point, creating a rectangular projection. All projections have a common bond in that they all must contain a distortion. Trying to portray a three dimensional surface on a two dimensional plane can lead to various forms of distortion including: areal, angular, scale, direction, and interruption. Areal distortion occurs when different areas of a projection are not consistent in size. An example of areal distortion can be found in the mapping of Greenland which is typically shown to be larger than South America, when in-fact it is one seventh the size. A map with no areal distortion is said to be equal-area. Shape distortion is known as angular distortion. A map with no angular distortion is said to be conformal. Scale distortion is when distances are not the same thro...