This week, Boston Public Schools announced that they were changing the maps in their classrooms from the Mercator Projection to the Peters Projection (below).
Now, my students have probably caught on that I like to use a lot of maps in my PowerPoints (here, here, here, and here). I have also always loved the scenes from The West Wing where CJ meets with the Cartographers for Social Equality on Big Block of Cheese Day. So naturally, when I saw a post about another, more accurate global projection–the AuthaGraph World Map (below)–that presented the sort of spherical Earth in a flat plane, I shared it on facebook. This post includes Hajime Narukawa’s TEDx talk (in Japanese) explaining what’s so good about his map and the relevant clip from The West Wing.
The post and discussion of it on facebook got me wondering 2 things:
(1) What projection is used in Google Earth, which I use to make most of my maps? why?
- There are some great explanations at this quora page. Basically, Google Maps uses the Mercator projection because it has a consistent north (top) and because, when viewed on a local level, things you want to see at right angles (like intersections) are at right angles. Most users of Google Maps aren’t looking at things on a global level so the distortions of the Mercator projection aren’t a problem.
- Google Earth, though, allows you to view the world as if it’s projected onto a sphere. I was relieved to remember that I do this, but I don’t remember how I turned on that setting. Therefore, all my recent maps from Google Earth are already less socially irresponsible.
(2) Why do I continue to use a Mercator projection in my classes, even though it stinks?
- Like with Google Maps, Classicists often don’t need to use a global perspective. Maps of the Punic Wars don’t need the eastern Mediterranean, and maps of Pompeii or Rome are very localized. A city-, Mediterranean-, or European-wide map is enough, and the Mercator’s emphasis on Europe helps show these regions pretty clearly.
- When I teach world history or show images of all of Eurasia, though, they are distorted. Admittedly, I’m much less likely to make a map on Google Earth for that class for five reasons: (1) the maps I’m showing are used to illustrate certain details, like trade networks in the Indian Ocean, that are harder to reproduce myself; (2) the projection allows me to show the entire world at once; (3) it’s too time-consuming to reproduce everything that I want in the maps; (4) it’s not my specialty so I’m less confident in replicating the maps; and (5) I’m used to the Mercator projection.
Admittedly, some of these objections–laziness and comfort–are less valuable than the need to show a flat map and my lack of skill and knowledge to reproduce a more accurate map with Google Earth’s spherical projection. So, until there are a wealth of historical global maps that don’t use the Mercator Projection, the best solution may be to more thoughtful about the ramifications of a map I choose from a search on Google Images, so that my powerpoint overcomes some of the Mercator Projection’s problems. For example, even though the political map on the left does not meet all the needs I would have for a map, it actually places the equator half way up the map and so avoids some of the Mercator’s distortion. Admittedly, this is not a complete or fully satisfying solution, but it may help to slowly chip away at injustices where we can.