Lab5: Map Projections

Conformal:
1. Mercator

Planar: 10,112.118968 miles

Great Elliptic: 6, 934.483772 miles

2. Stereographic

Planar: 9,878.038997 miles

Great Elliptic: 6, 934.483772 miles

Equal Area:

1. Behrmann Equal Area Cylindrical

Planar: 8,763.089124 miles

Great Elliptic: 6, 934.483772 miles

2. Bonne

Planar: 6,730.704827 miles

Great Elliptic: 6, 934.483772 miles

Equidistant:
1. Equidistant Conic

Planar: 6, 972.480093 miles

Great Elliptic: 6, 934.483772 miles

2. Azimuthal Equidistant

Planar: 8,341.411788 miles

Great Elliptic: 6, 934.483772 miles

     Map projections are often utilized to portray a part or all of the Earth's surface on a 2-dimensional flat surface; it always comes with some distortion and each projection has its own advantages and disadvantages. There are mainly three types of projections-- conformal, equal area, and equidistant (as shown in above examples), each preserving a different element of shape, angle, direction, distance, or area since a map projection cannot preserve all these features. In this lab, we sought to study the mapped distance between two cities, Washington D.C. and Kabul, Afghanistan and the differences based on the particular projection we were viewing. We measured the distance using two different methods-- Planar and Great Elliptic. Planar simply measures the distance using 2-dimensional Cartesian mathematics while Great Elliptic utilizes the intersection at the surface by a plane that passes through the center of that ellipsoid as well as the start and endpoints of the particular segment.
     The first two map projections, Mercator and Stereographic, reflect conformal map projections that preserve shape, angle, and direction. The conformal map projection may be useful for any tasks that require viewing the correct shape of the countries. These map projections are characterized by the 90 degree angle that is maintained by the latitude and longitude lines. This projection does not, however, preserve area or distance; for example, in the Mercator Projection, Antartica is enormously represented in comparison to the rest of the world. This type of projection is also useful because its directions are fairly accurate, which may aid in navigation. The main drawback of a conformal map would be the increasing amount of distortion as you get farther from the parallels.
      The next two map projections, Behrmann Equal Area Cylindrical and Bonne, reflect equal area map projections that preserve the area, as suggested by the name. This projection is advantageous in that the viewer is able to obtain a realistic visualization of the correct geographic sizes of different entitites. In addition, this map projection can be useful in showing distributions of geographic characteristics, such as pollution and population density. Despite its advantages, some limitations are that this map projection does not preserve shape, angle, distance, or direction. As you get farther from the center, the shape, angle, and direction can get increasingly distorted. In addition, distances can also be inaccurately represented due to it not being preserved.
     The final two map projections, Equidistant Conic and Azimuthal Equidistant, reflect equidistant map projections, preserving the distance of the Earth's surface. This projection depicts true distances that can be useful in mapping buffer zones, as seen by the missile buffer zone in North Korea shown in the lecture slides. Although the distances are true, depending on the type of measurement (eg. planar, great elliptic), the distance can be vastly different. Some limitations of the equidistant map projection is that this projection fails to preserve shape, angle, direction, and area. In addition, although this projection shows true distance, it is merely limited to distances from the center of the projection outward; it does not reflect the correct distance between any two random points.