Dead Reckoning(damninteresting.com)
97 points by repost_bot 8 hours ago | 9 comments
DavidPeiffer 7 hours ago
My favorite application of dead reckoning is the early 80's Honda system to display the car location on a map. While testing the system, there were times where the car showed itself off of the road. After looking into it further, they learned the map maker had taken some liberties with the exact position of the road, and the vehicle was correct.

Previous discussion: https://news.ycombinator.com/item?id=38135979

chneu 3 hours ago
Not dead reckoning related but for some reason your comment made me think of this.

Map makers make mistakes on purpose. This way they know when someone copies their maps. They look for these little tiny "mistakes".

beAbU 3 hours ago
My favourite example of some humorous dead reckoning, from this old copypasta:

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The missile knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position that it was, is now the position that it isn't.

In the event that the position that it is in is not the position that it wasn't, the system has acquired a variation, the variation being the difference between where the missile is, and where it wasn't. If variation is considered to be a significant factor, it too may be corrected by the GEA. However, the missile must also know where it was. The missile guidance computer scenario works as follows. Because a variation has modified some of the information the missile has obtained, it is not sure just where it is. However, it is sure where it isn't, within reason, and it knows where it was. It now subtracts where it should be from where it wasn't, or vice-versa, and by differentiating this from the algebraic sum of where it shouldn't be, and where it was, it is able to obtain the deviation and its variation, which is called error.

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cjs_ac 24 minutes ago
I think the delivery in this video is an important part of it: https://www.youtube.com/watch?v=bZe5J8SVCYQ
bombcar 0 minutes ago
eloisius 1 hour ago
This is like James Joyce describing a Kalman filter.
danw1979 1 hour ago
> the castaways had not seen any women in months, and based on the resulting unwanted attention, the indigenous people opted to evacuate before the English seamen became a problem.

chef kiss

thoroughburro 1 hour ago
The western barbarians seem to have been quite an uncivilised menace.
defrost 7 hours ago
Notable for deadpan correct use of Ear regardless . . .

Worth the read.

heresie-dabord 1 hour ago
Agreed, this article is well-written and rewarding to anyone capable of enjoying prose. Take the time to enjoy the article.

And for HN in particular, there is an ancestral link from the suffering crew of the ill-fated ship to the category of jobs that we have today.

I won't spoil it. But here is a clue: A.L.

foobahhhhh 1 hour ago
Spoiler alert! That was brilliant. I read it then went back and like "hold on...."
card_zero 4 hours ago
Oh irregardless. Clever. I admire how Alan spins these puns up with such casual breeziness, but of course I would say that because I'm a big fan.
louwrentius 4 hours ago
Damn interesting has an amazing collection of high-quality podcast episodes with amazing story telling. They haven’t released new episodes in a while, but their back catalogue is worth investigating.
card_zero 4 hours ago
It bugs me that the last episode is ominously called "A trail gone cold", and I wonder what went wrong.
foobahhhhh 2 hours ago
The problem with this article is it is realllly good and realllly long!
draw_down 47 minutes ago
[dead]
trhway 4 hours ago
The extremely hard travel around Cape Horn highlights the importance of the Panama and Suez channels, and i'm wondering whether Trump will surprisingly be vindicated by history for his steps toward getting the Northern Passage, ie. for the friendship with Russia and for the attempt to grab Greenland (or whether it will go down just the way it looks now :)
rokkamokka 3 hours ago
Vindicated? God, no
louthy 4 hours ago
> i'm wondering whether Trump will surprisingly be vindicated by history

He won’t. And those that went along with him will be judged poorly by it.

albert_e 4 hours ago
> the Drake Passage was the least impractical route for large European ships to travel around South America to access its west coast.

"least impractical"?

Unintentional double negative, I think?

Currently it conveys the meaning of being "most practical" whereas it was the opposite.

louthy 4 hours ago
I had to read that twice, but it’s correct I think. It’s an impractical route, but all the routes are… the Drake Passage was the least impractical of all of the routes.
throwanem 1 hour ago
It's correct and as intended. "Least impractical" denotes "most practical" but the double negative, which you accurately note is unusual but which is grammatical in this usage, calls attention to the specific connotation that all options are bad and this, though also bad, is nonetheless the most potentially serviceable of the lot.
542354234235 1 hour ago
We all know that language contains a lot of subtleties, but it is always interesting when someone breaks down exactly how those are used in some interesting prose.

And the prose itself is good too.

throwanem 39 minutes ago
I've been an eager student of grammatical nuance in English since my introduction to the written language at age two. I'm always happy to take apart an example of same and show its workings!
andyjohnson0 3 hours ago
I read "least impractical" as meaning "least worst" -- the best bad option.
4 hours ago
mattclarkdotnet 4 hours ago
Yeah, the thrust of the story is that it was the worst of all options
eru 1 hour ago
No. It was a best out of a bunch of bad options.