Lab 5

 

Map projections are a mathematical transformation of our 3D world onto a two-dimensional plane. Once on a 2-dimensional surface, you can observe the world on a flat, easily-transportable surface such as paper, which offers a lot of potential for specific analyses. Different types of map projections have different advantages. The Mercator projection, for example, is great for navigation because it preserves angles and directional relationships. While a projection may have undesirable distortions, the projection may be an excellent choice for large scale maps that provide a lot of detail. From this point of view, distortions are necessary to observe certain features of the earth in more detail.

The greatest potential in map projection lies in computer displays. Having the capability of projecting maps on a computer makes it possible to develop programs such as ArcGIS that are great tools for analyzing the Earth’s surface. ArcGIS and other similar software play large roles in informed decision-making. Computer capability in analyzing the earth also simplifies and quickens calculations and complicated analysis. In this lab, we were able to measure the distance using any unit we selected such as degree-minutes and miles, and the value was available with two-clicks of the mouse. This process saves the trouble of having to measure distance on a globe finding a bendy ruler then eye-balling and estimating the final value. This is only one example of a basic calculation that is facilitated through the usage of map projection.

Transforming a three-dimensional object onto a two-dimensional surface introduces certain distortions that can be a downfall of map projection as well. These distortions come in the form of shape, area, distance, or direction and are definite perils when it comes to not relaying incorrect or misleading information. It is important to understand and become familiar with how reality is distorted in order to increase geographic awareness and map appreciation.

The images above are examples of different map projection types that fall into three families: conformal, equal area, and equal distant map projections. The first 2 projections, Mercator and stereographic are conformal maps, which means they preserve the oriented angles between lines and curves. This map is used by sailors and pilots to navigate.  In preserving this detail, other details become distorted such as distance and size. On the Mercator graph, for example, the distance from Washington D.C. to Kabul, Afghanistan is measured to be 10,000 miles while the actual distance measured on a 3D graph is 7,000 miles. In this case, the distance has been stretched out. The equal area and equal distance map projections similarly preserves one detail while other details are distorted. Equal area projections preserve area and equal distance projections preserve distance.