lab #5

The maps above are created to show different features using different geographic method. As we can perceive from these maps, the equidistant maps preserve the distance; the equal area maps preserve the area; the confrontal maps preserve the angle locally. These characteristic projections display contrasting information for the viewers: the equidistant maps always havee very skwed angles and areas; the equal area maps have distorted angles and distances ; the confrontal maps project skewed areas and distances.

Each kind of projection has its own purpose and needs to present the world. As the projections transform the 3-D reference ellipsoid into a 2-D map, the on different levels distort the earth surface depending on various needs of the map. Therefor no maps represent the exact earth surface. And each projection has its own advantages and pitfalls. For example, the mercator maps mainly serve for nautical purposes as they always preseve right angles at the intersections of longtitude and latitude, being able to display the linear scale towards all directions. In the equal area maps, relative sizes are shown, but shapes and directions are distorted. This kind of maps make it possible for a visual presentation of the land on the earth foratlases and classroom use.

Althought all these projections are useful for people's lives in one way or another, there are many perils in utilizing them because while each kind of maps correctly portray some aspects, they distort others aspects at the same time. In other words, there is no one single exactly correct maps and there is no best map. The best map is the one which can show certain characteristics which we are looking for.

Despite the pitfalls of map projections, there is still musch benefitial potentials in using projections: we are allowed to view the geographic data in a 2-D way in a convenient and fast way. And I believe that it is always our pursuit to find out a better way to represent the world with the lowest level of inaccuracies.