Map Projections: Equidistant, Equal Area, Conformal

Map Projections



 Map Projection is the process of converting a spherical model on to a planar model, which makes it easier to view the whole world at once. In this process you have some trade-offs to make though. What features such as, distance, area, and direction of your map do you need to reamin accurate and which ones can be distorted. There is no way to portray a perfectly depicted map with no distortion on a flat surface. Distortions can be dealt with and researchers have studied hundred of diffrent kinds if maps to categorize them into three specific types to make it easier for people to pick the map that has acurracy in the feature they need. When choosing a map you have to look at your problem and see if it need accuracy in distance, direction, area, or angles. Which is the most important and which is the least important. Then you can choose whihc will be the most helpful; conformal projection, equidistant projection, or equal area projection.

 

Conformal map projections are most frequently employed in large scale maps such as topographic maps or navigationals maps. Conformal maps preserve shape and local angles, creating a system of longitude and latitude gridlines. Conformal maps also lead to accuracy in local directions. Conformal maps arent often used on the world scale but can be helpful in comparing two countries or two continents such as the Americas.

 

Equidistant projections preserve distance when its is calculated from a designated point. Directions are all true from the center outward but shapes are all distored the further you get from the center. A equidistant projection is very useful for pilots who need to know the distance of a trip or an example we used in class was the korean missile crisis. How far does the missile need to be able to shoot to get to its designated target.

 

Equal area map projections preserve areas throughout the map but distorts shape and scale as you near the poles very badly. These maps are most efficient when studying tropical areas near the equator because there is very little distortion in any features. It can also be useful when comparing smaller regional areas because distortion remains on the same level for the whole area basically.

 

Transforming something from being three dimensional to two dimensional is not an easy task and of course there is going to be trade offs involved in the process. Yes there are positives and negatives in map projections varying on the three categories. As a researcher you need to know which projection has the features most suitable for your study.