From the NYT's Sunday magazine (dated 20 Mar 2016):
http://www.nytimes.com/2016/03/20/magazine/the-secrets-of-the-wave-pilots.html
. This talks about various elements of ancient ocean navigation and
the problems in relying on modern GPS systems. This also ties to the
recent post about the Navy's decision to re-institute training for
celestial navigation. From the NYTs piece:
"To teach way-finding, the Marshallese use stick
charts, wood frames crosshatched like dream catchers to
represent swells coming from four cardinal directions, with
shells woven in to symbolize the position of the atolls. These
meant nothing to the first European explorers to see them,
just as Mercator projections meant nothing to the Marshallese.
Even today, local schoolchildren visiting the historical
museum in Majuro are sometimes baffled when they’re told that
the blue and green pictures on the walls are pictures of where
they are.
If ‘‘where’’ is both subjective and physical, what do you need
to know, precisely, to figure out where you are? From the
moment our nomad ancestors wandered out of Africa until a few
decades ago, locating yourself required interacting in some
way with the environment: following the stars or a migrating
herd of wildebeests, even reading a compass or a street sign.
Then, in the time it took to transition from rotary phones to
smartphones, we became the first unnatural long-distance
migrants, followers of step-by-step instructions that obviated
the need to look around at all. Over the last several years,
organizations like the United States military and the Federal
Aviation Administration have expressed concern about their
overwhelming reliance on GPS and the possibility that the
network’s satellite signals could be sabotaged by an enemy or
disabled by a strong solar flare. The United States Naval
Academy has once again begun training midshipmen how to take
their position from the stars with a sextant."
Joel Kovarsky