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While we're on the subject of maps-related bugs, I was recently borrowing a new Tesla Model Y and took it on a RORO ferry. After the crossing, the car’s GPS was convinced I was still at the port where I had departed from. I restarted it a couple of times, but nothing. I drove off using Waze on my phone instead of the car's navigation. The map on the car kept moving relative to the direction I was driving, so the navigation was showing me driving into the sea and eventually started complaining that it would be impossible to find a charger.

Approximately 5 hours later, just as I was about to arrive, the car finally managed to figure out my correct location.

Exciting trip, not a huge fan of Teslas, but their charger planning is really nice. It was very unpleasant to suddenly lose it.

I just genuinely wonder how such a bug can actually occur, surely you'd update the GPS fix more often than every couple of hours. Hard to imagine the car just suddenly couldn't get a GPS fix for hours either. But if it did somehow totally lose the ability to use GPS, the car must have a pretty good dead reckoning system given how well it was responding to my changes in direction.

On a vaguely related note, driving 3000 kilometers through Europe in an electric car was surprisingly nice. Certainly didn't affect the length of the trip nearly as much as I'd have expected, but it was certainly super annoying to try and figure out the optimal rate of travel on the Autobahn. Charging at Tesla's supercharges was vastly more expensive than I expected, the "fuel" costs weren't much lower than what you could easily reach with a diesel car.

I had a Volvo XC90 that “jumped” off the interstate and onto a parallel mountain road east of Knoxville. It did its best to track along those roads and somehow made its way into North Carolina. But even when I was back in Chicago, it was still stuck in NC trying to find a way off those mountain roads. Dozens of on/off cycles did nothing. I disconnected the battery overnight and that didn’t work. At the next service appointment, the dealer had to do a full firmware reset to wipe the memory and get it working again.

It amazed me that Volvo programmed an SUV to disbelieve that it could ever actually leave a road.

My guess would be:

1. Car entered ferry, loses GPS

2. Car entered dead reconning mode used for tunnels and such

3. Car left ferry, acquired GPS

Then either:

4a. Location via dead reconning vasty disagreed with GPS because the car doesn't know about the ferry's movements, triggering some kind of failsafe.

Or:

4b. There's just a plain old bug in the condition to switch back to GPS and maybe people haven't noticed because you don't get as badly desynced in a tunnel.

>the car must have a pretty good dead reckoning system

Yeah all the pieces are there: accelerometers and gyros for stability control, compass for navigation, and the wheel speed sensors give you exact distance traveled.

A practical issue is that GPS can be spoofed relatively easily. If autonomous driving became a thing, and ubiquitous, with vehicles that prioritized remote over local consistency, then a single GPS spoof could cause some interesting things to happen. This is probably a concern that does drive decisions, at least to a degree. It creates a weird scenario where you kind of need to trust GPS, but you simultaneously also can't treat it as authoritative.

OTOH creating a dumb user experience for a fairly common scenario, to try to preempt a hypothetical scenario is probably not a great idea. A fun problem to think about, though it may be completely unrelated to this issue.

> On a vaguely related note, driving 3000 kilometers through Europe in an electric car was surprisingly nice.

Having done a number of multiple-thousand km trips in Europe in an EV (not a Tesla, nobody buys those anymore) — it's amusing how non-EV muggles think this is somehow an ordeal. It's just fine! There are drawbacks: you do have to use your brain and plan ahead more than you do when burning dinosaurs. But I found that the 20-30 minute stops every 2h really improve how I feel after a day or two of driving.

Agreed about prices: there is gouging going on with some crazy margins. When charging at home, an EV is 2-4x less expensive per km than a gasoline-powered car, but when fast-charging on a road trip the cost of energy is nearly the same.

Back in the days of MapQuest there was a (usually) very good site called mapsonus.com, but it evidently had one of the ferries that crossed Boston Harbor in its map as a zero distance link.

Since it was offline, the bug was obvious although a bit frustrating - you had to put in multiple waypoints to make it forget its urge to send you on the ferry to Hull when you were trying to get to parts of the South Shore.

I suspect that my Tesla adjusts its location based on dead reckoning after losing GPS lock except that it assumes that I'm driving forwards. I.e. If I reverse out of my garage, then the map ends up in the wrong place and now I'm driving parallel to the road!
As you're mentioning a RO/RO ferry, recently, and Europe... are you sure you weren't in a GPS-denied environment, where the car (correctly) detected that GPS was jammed or spoofed and ignored it?
One hypothesis I can offer is that your car could not, for whatever reason, use assisted gps to download the almanach which relies on mobile networks. Gps devices that download the almanac via gps itself can take up to twelve hours (in higher latitudes i think)!
Possibly it was using WPS keyed to the ferry's WiFi and didn't consider the possibility that the ferry itself could move out of where it was registered (ie, the port)?
Civilian GPS (as in, the DoD’s Navstar) alone isn’t accurate enough to actually place you on a specific road. To compensate, auto navigation systems will snap you to the nearest road parallel to your current heading. Tesla likely didn’t consider the edge case of ferries and other off road situations in their mapping software and you hit some corner case bug.
Looks like others have reported similar issues. Entering a navigation route may help?

https://teslamotorsclub.com/tmc/threads/map-location-and-rou...

>On a vaguely related note, driving 3000 kilometers through Europe in an electric car was surprisingly nice.

I did 2 cross country road trips here in the US (~5000mi/8000km total) and had a similar experience. The nav's automatic charger routing did a great job, and we had 0 issues with charging.

My farming GPS does this every time I ship it with my vehicle to a new continent.

I always figured it has some code to get a quick location, and it assumes that location is very close to the last time it got a sat lock.

I just ignore it for the first day, then it comes good.

I wonder if it's using a compass and odometry (distance) with dead reckoning. A strange choice when GPS is available, but it would account for the map moving in the car's direction and it not changing locations when it moved without rolling (ferry).
I remember cars in the early 2000's doing this. Haven't seen that behavior in years.
Context is confusing because we arrive in the middle of a story arc, at a point where an unrelated tech snafu happens.

The story arc is about a lost airtag that is living it's secret life in Mexico.

The link is for a post where Apple decides the distance to it's location in Mexico is greater than the circumference of the Earth.

GPS has an altitude component so maybe it thinks either the AirTag or the tracking phone is really high up?
Directions suggest an average speed over 500 mph. Not bad for driving.
It’s the speed of a passenger flight, but I wouldn’t want to spend 57 hours aboard.
Tangentially, why won't computerized maps - e.g., Apple Maps, Google, etc. - show a scale? Generally they'll show one as you pinch/zoom, but it disappears when you release your fingers.

Sometimes I just want to eyeball distances, and not plug in addresses and request routes for everything.

I know not everyone always wants it, but a scale is a fundamental feature of mapping! Scale almost defines mapping.

Edit: One reason I ask is because I suspect some technical limitation.

It’s purely a UI thing, the same (misguided) reason scrollbars disappear.
I thought it'd be cool if the scale were shown by some channel, like coloring roads (pink at neighborhood scale, blue, green as you zoom out) so you could intuit the scale at a glance.

With map simplification and symbolic markers (roads are the same thickness at multiple scales) it can be really hard to figure out distances. I was once going to a less populated area, based on my local intuition I thought the distance between two locations was a maybe 30m walk max if I missed the bus, but it turned out it was a 3h walk.

Actual distance about 3.2k miles plus equator length of 25k miles plus what else?
Altitude
Oh wow, a bug
In Apple Maps? Unpossible!
Except this one is not on the windshield.
I made a comment earlier that was rightly flagged for its tone, and I would like to restate the technical point more constructively.

The post author, Dan Piponi, clearly knows about fractals, but his post raises the question of whether asking Fermi questions in interviews is actually effective. I am skeptical that such questions would have prevented this type of bug.

I suspect the issue stems from small measurement imprecisions accruing over long distances, which is—in my view—tied to the fractal nature of roads traversing natural landscapes.

However, as others have pointed out, it may also be tied to road closures: if closed segments are set to a higher length internally (to discourage routing), these values might be getting summed up blindly over longer distances.

None of these issues would have been prevented by being good at estimating quantities alone.

Apologies again for the unconstructive tone of my previous comment.

Here's a Fermi-ish question: given the fractal nature of typical landscape, should a truck driver budget for 10 times as much time as would be predicted by using the known typical speed of the truck and the distance as the crow flies?

(Aside: the nearest grocery store to my house is 1 mile away but the shortest route by car, as measured by the car odometer, is 10 miles.)

A pure spirit is required to admit your own mistake. Don’t be let down by an error, never lose the opportunity to fix it. May this be of example to everyone to keep improving this already wonderful but not perfect community.
I’ve had that bug a few times. I think it’s related to some roads being closed and/ or under reconstruction. I’ve seen this happen multiple times on the same route, and it always fixed itself after I passed the construction site.
So it might be a hack to get it to take another way -- rather than invent some way of marking a road section as being closed, mark it as being 1000 miles long?
Maybe they are running into https://en.wikipedia.org/wiki/Coastline_paradox
It's unlikely that would cause a 10x increase, especially since the directions are presumably aligned to roads of non-vanishing length.
context?
I went back to their posts in November for this

> One of my AirTags is inexplicably 1600 miles away in Texas. It's one of my floating ones that I throw into bags when traveling as needed.

> Maybe it dropped out of my bag only to be found by someone who thought it'd be fun to confuse the owner. Or maybe it became e-waste to be dumped in another country.

The distance is more than the circumference of the Earth. If you wrapped a rope around the planet at the equator, the length would be around 25k miles.
Seems like the author of the linked post has a lost airtag located in the abyss.
Looks like a bug that I hope someone will have a fun time fixing.
You wouldn't imagine ...

I have seen API calls you people wouldn’t believe.

Requests hanging off the edge of the load balancer, Ethernet tubes glittering in the dark.

Latency logs reporting some API calls that took longer than the age of the universe.

Their means and percentiles burning on the shoulders of weekly reports.

Plot points dying at the edge of y axis

... like tears in the rain.

Fixing bugs. At Apple. OK.
Loved the comment about the fractal shaped path.
Maps has gone backwards on CarPlay, too. Hysteresis is completely broken - I stop at a traffic light and the map will jump back and forth between two resolutions, often once a second, which is extremely distracting.

I also love that Find My says my partner was "last seen" at home "8,912 days ago".

Apple just doesn't give as much of a shit any more.

As one of the commenters pointed out, altitude.

A geostationary orbit is ~26,000 miles. Dollars to donuts, that's where it is.

48 137 km.
The most annoying thing about iPhone Maps for me is the inaccuracy of the direction indicator. I've googled and it doesn't seem to be a universal complaint even though I've experienced this on multiple devices over the years even after following instructions to re-calibrate multiple times. Maybe I've just been unlucky.

It intensely frustrating to use maps for direction finding while walking or cycling when the app is telling you are facing one direction when in fact you are facing another.

It is easily 29,905 road miles away.

If you put all of your blood vessels end to end they would go to the moon and back.