The Significance of Map Projections
Depending on what one is looking for, map projections can either significantly facilitate or hinder the presentation of geographical data. The three main classifications for map projections are as follows: conformal, equal area, and equidistant. Conformal projections preserve angle measurements, equal area projections preserve areas, and equidistant projections preserve distances. However, each projection lacks the preservation of the other two dimensions, and greatly distorts their measurements. I was unsure of how significant these distortions were until completing this lab.
The two conformal projections I chose were the Mercator Conformal Projection and the Eckert I Conformal Projection. It is quite evident that these two projections differ in their representation of the shapes of the continents. Because of this, the area of the continents is not preserved. Even more evident is the misrepresentation of distance: the Mercator reports the distance between Washington D.C. and Kabul to be over 10,000 miles and the Eckert I reports it to be just above 6,700 miles.
The two equal area projections I chose were the Bonne Equal Area Projection and the Sinusoidal Equal Area Projection. These both obviously distort angle representation relative to the graticule. They distort the distance between the two cities as well. The Sinusoidal projection represents this distance as just above 8,000 miles while the Bonne projection represents this distance to be just above 6,700 miles. Furthermore, the shapes of the projections are notably unique, and might not be the most easily comprehended to a novice geographer.
The two equidistant projections I chose were the Two-Point Equidistant Projection and the Equidistant Cylindrical Projection. Even while these two projections both claim to represent distance equally, there is still a discrepancy in the reported distances between the two cities. The Two Point Projection reports this distance to be just above 6,600 while the Equidistant Cylindrical Projection reports this distance to be just above 5,000 miles. Therefore, it is important to evaluate the strengths of various map projections; even within their relative classifications, there are still distortions.
No comments:
Post a Comment