Many years ago, when I was in public school (can't remember which grade, I think it was sixth or seventh), I was tasked with drawing a map of the world. I can't remember what I used as my source (it may have been a globe) but the map I ended up with did not look much like the Mercator projections I was used to. I had drawn the lines of lattitude and longitude as a grid with each line equidistant from the next. As you got further from the equator, the geography appeared to be compressed in the north-south direction. All this time I figured I had done something that wasn't quite right. Perhaps the lines of lattitude were spaced farther apart the further you got from the equator and my map didn't reflect that. I speculated that the lines would appear equidistant if you were looking at the globe from the side. Or, if you were to slice the earth along the lines, each slice would be of equal thickness. For some reason, I never remembered to check this whenever I looked at a globe.
It wasn't until several days ago that I realized what had happened. I had drawn a straight cylindrical projection map, which is basically in between a Mercator and a Peters projection. The reason the geography looked compressed vertically the further you got from the equator was that it was actually being stretched horizontally. It was not an equal area map (like the Peters), nor was it conformal in terms of compass direction (like the Mercator). The Peters stretches the geography vertically as you get closer to the equator, the Mercator as you go away from it. My map did neither.
For a comparison between the Mercator and Peters projections, and what their respective purposes are, read this article at about.com.
Proponents of the Peters projection map claim that their map is a good, fair, and non-racist view of the world. They're comparing their map to the almost-defunct Mercator map. Unfortunately, geographers and cartographers agree that neither map projection is appropriate for use as a map of our planet.
Yes, the Peters projection is more accurate when it comes to relative surface area of the various countries. However, like all 2D projections of the spherical earth, it distorts the appearance of the geography. Proponents of the Peters map say that the Mercator projection makes the countries of Europe and North America appear larger than the developing countries (which is true).
This was convenient, psychologically and practically, through the eras of colonial domination when most of the world powers were European. It suited them to maintain an image of the world with Europe at the center and looking much larger than it really was.
Here comes the political correctness. Interestingly enough, the very next sentences seem to contradict this idea:
Was this conscious or deliberate? Probably not, as most map users probably never realized the Eurocentric bias inherent in their world view. When there are so many other projections to chose from, why is it that today the Mercator projection is still such a widely recognized image used to represent the globe? The answer may be simply convention or habit. The inertia of habit is a powerful force.
I guess it was all subconscious on the part of the map users of old. Back to the article at about.com:
The Mercator map was never intended to be used as a wall map and by the time Peters started complaining about it, he was creating a mountain out of a molehill as the Mercator map was well on its way out of fashion.
When it comes down to it, the map you choose should be the one that's best for the use to which you intend to put it. Other than making people in Africa and South America feel better about the sizes of their countries, I don't know what practical use the Peters map would be. Choosing the Peters solely for this reason, especially when a different projection is more useful, is giving in to the siren song of political correctness.
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