Lab 5: ArcGIS Projection

       All map projections experience distortion to an extent which may or may not be acceptable for certain applications. In this week's lab we used ArcGIS to create our own maps using Equal Area, Equidistant, and Conformal  projection forms. We defined two cities, Washington D.C. (W.D.C), and Kabul, and then measured the distance between both locations in each map-projection. By using different projection techniques, it became possible to see the relationships different map projections have to one another when comparing map-scale properties. Each projection type has pros and cons, and understanding a few basic concepts around how data is distorted can lead to choosing better maps. Scale representation is easily manipulated by changing data inputs, thus it becomes integral to have accurate definitions when representing data.

In the first series of maps I used sinusoidal and cylindrical projections to show equal area properties. Equal area maps allow the earth's masses to preserve areas equal to their true areas on Earth. The sinusoidal projection is also known as a pseudocylindrical projection because of the way it distorts shape. This type of distortion is deceiving to the eye when considering equal area properties yet remains mathematically proportional despite any perceived illusions. The cylindrical equal area map has a lot of distortion near the poles. Due to this, some studies should use other projections types to answer questions. The distance from W.D.C to Kabul is 8,097 miles and 10,130 miles--sinusoidal and cylindrical projections respectively.

On the other hand, equidistant projections preserve distance between a set or sets of points where distances over the map will match true distances on earth. For my equidistant representations I used two-point equidistant and equidistant conical projections. What can be noticed are the unique angles each map features. Because the distance between a set of points is preserved on equidistant maps, they can prove to be beneficial to individuals looking to define time as a value when navigating between places. One can notice many distortions about the equidistant maps I used in their use of shaping continents and angles. The distance from W.D.C to Kabul is 6,640 miles and 7,000 miles--two-point equidistant and equidistant conical projections respectively.

Last of the maps are conformal projections which preserve shapes locally. Through this, conformal maps preserve shapes of land masses and the visual familiarity most people have with maps. I chose to use Miller Cylindrical and Mercator projections for my conformal maps. The popularity of these maps makes them important in relaying conceptual information. It should be noted that inaccuracy of quantitative values makes this map less useful when calculating data or using numbers to represent accurate information. Regardless of the errors found within such maps they are important in education and theory where abstract concepts can be relayed through visual data and less on numbers. The distance from W.D.C to Kabul is 10,203 miles and 10,098 miles--Miller Cylindrical and Mercator projections respectively. By completing this lab I have gained a better understanding of map projections and the various types of representations that exist to relay spatial information that defines the earth.