Advantages and Disadvantages of Map Projections

Different map projections can have certain benefits and disadvantages. Three types of map projections were represented in the current assignment – equal area, equidistant and conformal. As the name suggests, equal area maps preserve areas of features. To preserve areas, “other properties—shape, angle, and scale—are distorted” (arcgis.com). Equidistant maps preserve the distances between different points. The drawback of equidistant maps is that scale cannot be preserved throughout the entire map. Lastly, conformal map projections are designed to preserve a local shape. As described on arcgis.com, “To preserve individual angles describing the spatial relationships, a conformal projection must show the perpendicular graticule lines intersecting at 90-degree angles on the map. A map projection accomplishes this by maintaining all angles. The drawback is that the area enclosed by a series of arcs may be greatly distorted in the process.”

Experimenting with various map projections in ArcMap made the benefits and disadvantages of map projections readily apparent. To project a three dimensional object – namely Earth – onto a two dimensional medium certain distortions must take place. Different projections are designed to mitigate particular distortions. Yet, the mitigation of a particular distortion results in the exacerbation of another distortion. For example, the Mercator projection is designed for little distortion of shape near the equator. To provide the lower distortions near the equator, greater distortions are evident near the poles. This can be recognized on a Mercator projection of the globe. Antarctica appears to be much larger than it is in actuality.

The distortions that arise with map projection are inevitable. As previously noted certain distortions can be exacerbated in map projections. Conversely, certain distortions are lessened for a variety of purposes. For instance the equidistant conic projection defines two standard parallels that feature no distortion. If areas along these parallels were of interest, this type of map projection would be suitable. This is just one example of the mitigation of distortions. The complete description of distortions is not the intent of this paper.

Evidently, no one map can be described as the greatest overall. Certain projections work best for certain situations. The numerous types of map projections each represent a set of distortions – some of which are great and others that are lessened. The six projections illustrate in the previous example provide additional insight into map distortions. The six projections provided early are: GCS WGS 1984, Mercator, Equidistant Conical, Equidistant Cylindrical, Berhmann, and Cylindrical Equal Area.

Works Cited

"ArcGIS Help 10.1." ArcGIS Help 10.1. N.p., n.d. Web. 27 Jan. 2015.