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Nature is full of clues to help you find your way – if you know where to look. Stuart Heritage lets go of the GPS to learn the art of natural navigation from pioneer Tristan Gooley
[...] How to navigate in a city
Look for satellite dishes. They all point towards the equator. In London, that is roughly south-southeast.
Find an 'invisible handrail' and use it to remember your bearings. In the countryside, this might be a river. In a city, it could be a main road.
Look at a tree. Do the branches point a certain way? That's probably south. Are the leaves on those branches smaller than the leaves on the opposite side? That's definitely south.
Use the sun. It rises in the east, sets in the west and moves through the southern sky, giving you a very basic compass.
Need to get home? Head against the flow of people at the start of the day or with the flow at the end and you are pretty much guaranteed to find a station.
Source: Ditching the satnav: the lost secrets of natural navigation
(Score: 5, Informative) by Whoever on Sunday May 13 2018, @04:45AM (6 children)
That's not dead reckoning. Dead reckoning is working out your current position from a known starting point then using velocity and time to calculate your current position. In other words, NOT using terrain.
(Score: 2) by legont on Sunday May 13 2018, @06:36PM (5 children)
That definition, my friend, is similar to spherical cows in airless space.
In real life there are variables, such as wind, which can not be predicted with any reasonable accuracy for low altitude flying and, among other things, depends on terrain. Yes, the pilot initially estimates course and time, but then constantly adjusts it using outside clues. That's what pilot instructor would tell you when flying "dead reckoning" - get your attention outside the cockpit. He would ask you where the wind is currently coming from and with what speed and how you should adjust your flight plan.
A typical novice procedure is to fly pre-calculated plan to a check point, use map to calculate the error, re-calculate the plan.
Regardless, the whole point is to be aware of surroundings as opposed to putting your life into technology, such as GPS.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 2) by Whoever on Sunday May 13 2018, @07:01PM (4 children)
And when you are in a boat on the ocean: how visible is that terrain? Or in a plane above cloud cover?
Your instructor doesn't know what dead reckoning is. His ignorance does not change the definition. He may be skilled at flying and navigating, but not so good with semantics.
(Score: 2) by legont on Sunday May 13 2018, @07:47PM (3 children)
The most famous example of extreme dead reckoning was a first flight across Atlantic ocean by Charles Lindbergh - NY to Paris https://en.wikipedia.org/wiki/Charles_Lindbergh [wikipedia.org]
He flew most of the way below low clouds level over the ocean to use waves direction and shape to estimate wind drift. He managed to hit coast line within a few miles of his plan. That's how it is done without the technology. Read the book - it's fascinating https://en.wikipedia.org/wiki/The_Spirit_of_St._Louis_(book) [wikipedia.org]
A few short years later Antoine de Saint-Exupéry flew regular air mail Paris to Argentina and back using the same technique. This book is a masterpiece https://en.wikipedia.org/wiki/Night_Flight_(novel) [wikipedia.org]
Nowadays, even military lost the art. Here is an example - they had to follow their tanker back after "software glitch" https://it.slashdot.org/story/07/02/25/2038217/software-bug-halts-f-22-flight [slashdot.org]
But good flight schools still teach it - highly recommended - very useful even in real life driving.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 3, Touché) by deadstick on Sunday May 13 2018, @08:59PM
Alcock & Brown, among numerous others, would like a word.
(Score: 2) by Whoever on Sunday May 13 2018, @09:52PM
I don't understand what that has to with the definition of dead reckoning.
(Score: 3, Informative) by AthanasiusKircher on Monday May 14 2018, @01:07AM
Sorry, you still have no idea what you're talking about. You're talking about the use of VFR (visual flight rules) rather than instrumental flight rules. Within VFR, there are a number of techniques.
Navigation by visual landmarks etc. is known as "pilotage." Navigation WITHOUT visual landmarks is known as "dead reckoning." In the latter, you base estimated position on measurements of travel alone -- mostly speed and elapsed time, but corrections can be attempted on measures conditions too. Originally the term was developed for ships at sea with no visible landmarks -- so speed/direction and elapsed time were the main factors used for dead reckoning, but known ocean currents, wind conditions, etc. could be factored in as correction factors for the estimate.
Looking around at landmarks, terrain, etc. (which you referenced in previous posts here) is pretty much the OPPOSITE of dead reckoning. Seriously... Look up any definition.