Lab #5

Map Projections

Map projection is one of the key components in representing the Earth, (that and coordinate systems). Map projections; project a 3-D image to a 2-D image. This means that if you have a globe it becomes projected and the entire surface area of the globe becomes placed onto a flat surface (map). The one way of doing this is getting the globe project a light on to it, doing this would put an image on to that flat surface. No map projections can be perfect. That is why there are 3 different types of map projections.  The three different map projections are conformal, equidistant and equal area. Each one of these have specific characteristics that makes them special which gives advantages and disadvantages over the other projections. The real definition of map projection is “a process of mathematical conversion”.  There are only 3 known ways to get map projections from a plane, cone and cylinder.

Conformal map projection has the parallels and meridians intersecting perfectly at the right angles. The greatest strength to this map projection is that it basically preserves the shapes of the continents on the map. Meaning that continents like North America or Asia will be stretched making one look abnormally long or short. Shown above shows a Gull Stereographic and a WGS 1984 PDC Mercator map projection each showing that most of the continents shapes are preserved. The part of the map that is not preserved is Antarctica which is stretched.  Conformal maps are bested used for navigation or meteorological charts.

Another category of map projection is equal area map projection. Equal area map projection has the area of the map are the same in relationship to the areas on earth. Basically what this means is that the area’s on this map is preserved. Shown above are Bonne and Molloweide equal area map projections. Even though the shapes of the map may not be on the perfect right angles like the conformal map projection, it maintains the area meaning that Antarctica is no longer stretched or the largest shape one the map.

Finally is the equidistant map projection. An equidistant map projection is when the distance from the center of projection to any other point is equal in all distances. This means that the distends from one standard point is preserved. Equidistant map projections are used for radio, seismic mapping and navigational purposes. In the maps shown above the equidistant cylindrical and equidistant conic maps display that the distance between two different points are preserved in an x axis area.