Mapping Hacks

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Chapter 3, Mapping Your World

#32 Hack on Base Maps in Your Favorite Image Editor

HACK

featuring political boundaries. (Actually, the population growth map shows

political boundaries, but it also completely omits places for which no data

was available—e.g., Greenland, Western Sahara, Eritrea, et al.)

Although we are philosophically opposed to the social and economic ine-

qualities that political borders serve to maintain and foster, there is no deny-

ing that the same political borders offer a very immediate source of context

to the stories we can tell with maps. From a storytelling context, borders

offer a way of breaking up huge landmasses into smaller places that people

have heard of, and maybe know something about. Wouldn’t it be nice to

have some of this lovely Earth imagery show international boundaries, as a

way of offering more context to the other things we’d like to display on a

world map?

At this point, a professional digital cartographer might reach for his GIS

software and start loading vector layers, but we wanted something easier.

For starters, where to get a decent vector layer that represents the world’s

current set of political borders and isn’t encumbered by licensing restric-

tions? One easy answer is the Generic Mapping Tools,orGMT, which

includes a free, reasonably current set of international-boundary vectors at a

reasonable resolution. GMT is covered in great detail in ...