This is the third 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.
Cartographic challenge: Mapping Neighborhood Meanders
Solution: The GPS
The Global Positioning System is a flock of 27 or so satellites continuously buzzing around Earth. These birds are equipped with atomic clocks, and they broadcast their positions every second at the speed of light. Receivers coupled with software and clocks of their own can use these signals to determine positions anywhere on the surface of the planet or in space by comparing the time the signal was sent to the time the signal was received to determine distance to a satellite. Then trilateration is used to determine position. Receivers placed in planes, cars, or one’s backpack are being used by millions to guide aircraft, help motorists find their destinations or, in the case of Out of Eden, record the progress of a really long walk.
Slow journalism means meandering, loitering in places, soaking up the stories every mile, or maybe every few feet, depending on your pace and purpose. Why not apply space-age technology to map a global trek? Crazier things have been done. An inexpensive GPS receiver that Paul carries in his backpack enables detailed mapping with efficiency and accuracy any 1950’s explorer would deem unfathomable. Meanders in cities often occur at 90 degree angles, as shown on the map below of the exact locations (dark red dots) recorded from Paul’s GPS tracks through a portion of Jeddah, Saudi Arabia.
Zooming in further on the image below we see Paul’s tracks (moving from right to left) cross a highway (was there a tunnel?), loiter for a while, and continue on a steady, faster pace to the northwest.
So a big thanks goes out to the U.S. Department of Defense for creating and supporting the Global Positioning System because it enables tracking the Walk in minute detail, paving the way for super cool geo-multimedia features such as Walking Jeddah and Walking Jerusalem. See the full GPS track of Paul’s 2,806 miles traveled on the Completed Route Map.