This is the first in a series of short essays by Jeff Blossom, Chief Cartographer of the Out of Eden Walk. Jeff will periodically offer an inside view of the project’s map creation process by highlighting different mapping challenges and solutions.
“I’ll be walking 21,000 miles over 7 years, and I want maps to be a key part of the story.”
That’s what Paul Salopek said to me shortly after entering my office at Harvard’s Center for Geographic Analysis in April of 2012. As a cartographer and geographic information specialist, I’ve seldom heard sweeter-sounding words. A cartographer’s dream job is to travel the world (with Paul, it’s been virtual travel so far, although I will join him on part of his walk) and make maps. And that’s exactly what I’ve been able to do, building maps ranging from global to neighborhood in scale, from ancient migrations to traversing the modern world. In this essay series, I hope to provide insight to into the creation process of the OOEW maps by highlighting some of the unique challenges and solutions.
Cartographic challenge: Symbolizing Human Migration
Solution: Smoke Style Brush
Maps are representations of phenomena that occur in geographic space. Choosing symbols that intuitively communicate these phenomena is fundamental to successful cartography. Every map should have a purpose, and when discussing the purpose of a human migration map, Paul wanted to convey the “ghostly pathways of our ancestors” and how they moved in “bands, and waves” across and over the Earth. Fossil evidence and genetics give us a pretty good idea of our ancestral pathways. But how, exactly, does one depict this vivid description on a map? A simple line on a map just doesn’t do it justice. Searching and experimenting with different line symbols for hours may seem like an alien task to most, but it is one of these peculiar things we cartographers do, and my search ended when I found the Smoke Style Brush: when applied to a vector line in Adobe Illustrator, it produces the purple wisps shown in the image below. Add a directional arrow, and this becomes the ghostly path of our ancestors.