This assignment revealed many interesting aspects of the map
projection process. The first piece of
information I learned was that there are several different ways to measure
distance between two points on a map. In
addition, different map projections represent these distances with different
values. For example, using the planar
measurement, Kabul to Washington DC was 10,141 miles in the Mercator
Projection, 8,329 miles in the Hammer-Aitoff Projection, 9,919 miles in the
Stereographic Projection, 8,341 miles in the Azimuthal Equidistant Projection,
8,763 miles in the Behrman Cyinder Projection, and 6,919 miles in the Two-Point
Equidistant Projection. Overall, the
Great Elliptic and Geodesic measurements were the most consistent (and always identical
to each other) while the Planar measurement was the least consistent. The rest of the data is stored in the table
below.
While
no map was perfect, each projection had strengths and weaknesses. The Hammer-Aitoff Projection and the Behrman
Cylinder Projection were both very good at preserving areas; Greenland was not
bloated like it is on most maps, and Africa took up its due space. However, in the Hammer-Aitoff Projection, the
shapes of the Pacific Rim nations (such as China and the United States) are
heavily bent. In the Behrman Projection,
Africa is stretched vertically and Greenland is squished vertically. Both maps, in this sense, fail to convey the
shapes of the world.
The
Stereographic Projection and the Mercator Projection both preserved the shapes
of individual countries nicely. In both
projections, the United States looks like it does on the globe. The same is true with Greenland and with
China. However, the relative areas of
these countries differ greatly from reality.
In the Mercator Projection, Greenland looks bigger than the continent of
Africa. Even more peculiar is the
Stereographic Projection, in which the United States was rotated on its side
about seventy degrees and Australia appears several times the size of South
America. The planar distances in these
two maps between Washington DC and Kabul also differ the most from the actual
distance. Likewise, the equidistant maps
had shortcomings. Both the Azimuthal
Projection and the Two-Point Equidistant Projection reported relatively
accurate planar distances between the two cities, but distances between more
Pacific cities came out distorted and the shapes of countries were very inaccurate.
For
most applications, it seems a hybrid map style is most suitable to depict the
world. An equal area map will distort
angles and distances. A conformal map
will distort distances and areas and an equidistant map will distort angles and
areas. In a few applications—such as
examining the missile range of North Korea—one of these three partially perfect
styles may be needed. But in most cases,
one must compromise in order to get a good depiction of the globe’s
geography. For most applications, the
best map will have slightly inaccurate angles, distances and shapes. That way, none of the three elements is too
distorted.
Projection Type: | Hammer-Aitoff | Behrman | Stereographic | Mercator | Azimuthal | Two-Point |
Planar Distance | 8,329 miles | 8,763 | 9,919 | 10,141 | 8,341 | 6,919 |
Geodesic Distance | 6,934 miles | 6,934 | 6,934 | 6,934 | 6,934 | 6,919 |
Loxodrome Distance | 8,112 miles | 8,112 | 8,112 | 8,112 | 8,112 | 8,093 |
Great Elliptic Distance | 6,934 miles | 6,934 | 6,934 | 6,934 | 6,934 | 6,919 |
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