Friday, June 3, 2011

Freeing the Prisoners of the Mercator Projection

Travel writer Robert Kaplan recently observed in his stereotypically elaborate prose that we're all “prisoners of the Mercator projection.” Andrew Exum’s point that it’s a “great name for a band” aside, Kaplan is actually on to something. We imagine maps are objective, particularly familiar ones like the Mercator. In reality, nothing but our historical biases defines what’s up, down, left, and right. Small changes make big differences in what story a map tells, and alternatives to the Mercator can give new meaning to world events.

The central concern of mapmaking is 'projection': how physical space is visually portrayed. The world is a 3D surface, but maps are a 2D medium; we need to ‘unpeel’ the globe onto a paper. The aforementioned Mercator projection has assumed its Stockholm-syndrome hold on our spatial concept of the world because it’s based on navigational absolutes: the lines of latitude and longitude. While useful for traversing the triangle trade, the Mercator projection vastly distorts the sizes and shapes of continents, leading to a profound overemphasis on Europe and North America (The West Wing described this best).

One alternative is the Peters projection, which is area-normalized: it a
djusts latitude so that the actual sizes of continents are consistent across the entire map. At first jarring, this projection is closer to the 'truth'-- what you would see on a globe-- than the Mercator projection. South America and Africa are enormous, and Europe emerges as just another small Asian peninsula.

Yet even the Peters projection contains deeply-encode
d biases about how we view our world. Walk into any cheeky anthropology department and you're likely to see an upside-down map, with south at the top. It doesn't take a self-righteous lecture on Eurocentricity to realize how unfamiliar the world looks when China takes center stage. If the department is especially progressive, they'll sport an upside-down Peters projection, which is intimidatingly oceanic.

For maps of smaller areas, like individual countries or cities, why not abandon north and south altogether? In most cases the interesting axis of topographic or historic information won't be so conveniently polar. The expansion of the United States was the story of a frontier gradually being pushed forward, not a line moving to the left. Why not portray it from some point over the Atlantic Ocean, looking west over successive waves of expansion? The 2010 Times Atlas of World History tentatively moves in this direction with a map whose perspective is nearly as informative as the information it includes. Similarly, the same Atlas' treatment of the Mughal Empire abandons a rigid north-south axis for one that correctly draws the eye towards the passes to Central Asia. Kaplan’s already argued that a trans-Indus axis is far more important than the geological concept of a 'subcontinent.'

So why stop at a single region? Why not change our entire concept of a global map to emphasize the realities of geographic and human relationships rather than an arbitrary system of grid lines? After all, it is only the coincidence that magnetic rocks point towards somewhere n
ear Greenland that we think of north as 'up' in the first place. What is preventing us from designating any point on the globe as the 'north pole' and drawing a new map from that reference point?

In fact, it's nothing but our own biases. The mental gymnastics required to imagine unpeeling the globe with a point other than the North Pole for reference get tricky, but luckily we have computers to help us. An enterprising Dutchman has written a program to perform just this task, and the results are stunning. The first thing you notice about a map drawn with the 'pole' somewhere new is how wrong it looks. All of a sudden, the Mercator projection (which is what the program is rendering) is obviously, completely inadequate. "Europe doesn't look like that," you think, forgetting that any Mercator map is equally distorted, no matter where its poles. The distortion just happens to now be located somewhere we think we know well.

A map tells a story, and the map of the 21st century world can tell no other story but globalization. Continental blobs separated by swathes of blue don’t tell us much about our planet as a coherent whole; the need for navigational aids fades in comparison with the need for understanding. This projection-- with the poles in the Indian and Pacific oceans-- minimizes the distortion to land while joining together the continents into one large, human habitat. At a glance, grand trends in our history are made obvious: transcontinental flights passing over Greenland recall the quest for the Northwest Passage; the steppes of Central Asia assume their easily-traversed centrality; and bottlenecks like Hormuz, Malacca, Panama, and Gibraltar are but gates to the vast oceanic superhighway. This is a map of global human history, a map truly for our time.