[HN Gopher] What happens to Google Maps when tectonic plates mov...
___________________________________________________________________
What happens to Google Maps when tectonic plates move? (2020)
Author : dmitrysergeyev
Score : 208 points
Date : 2024-03-23 20:36 UTC (1 days ago)
(HTM) web link (nautil.us)
(TXT) w3m dump (nautil.us)
| latchkey wrote:
| Discussions on similar submissions:
|
| _What Happens to Google Maps When Tectonic Plates Move?_
| https://news.ycombinator.com/item?id=22146454 (January 25, 2020
| -- 2 points, 0 comments)
|
| _What happens to Google Maps when tectonic plates move?_
| https://news.ycombinator.com/item?id=22145303 (January 24, 2020
| -- 188 points, 53 comments)
|
| _What Happens to Google Maps When Tectonic Plates Move?_
| https://news.ycombinator.com/item?id=12216474 (August 3, 2016 --
| 2 points, 0 comments)
| croemer wrote:
| Last one didn't have much of a discussion. 0 comments :D
| latchkey wrote:
| I get the joke. However to be clear, I included it because it
| contained a link to another site that was rather interesting
| because it went to SA instead of Nautil.
| politelemon wrote:
| If you want to dive even deeper into datums around the world,
| there's a site dedicated to it: https://www.asprs.org/asprs-
| publications/grids-and-datums
|
| You'll find many countries in there with a bit of history of
| their datums and how they arrived at their present state. It's a
| dry reading that can be fascinating at the same time.
| hnburnsy wrote:
| Well since the author did not talk to Google we will not find out
| by reading this article.
| amelius wrote:
| In their defense, the tectonic plates will have moved a __lot__
| before you can expect to get any response from Google support.
| bluefirebrand wrote:
| Those will be interesting patch notes for google maps
|
| "we removed most of the gulf islands, part of BC, Washington,
| Oregon, and California" ...
| bell-cot wrote:
| At least that's guaranteed to be extremely far in the
| future.
|
| Vs. "we removed Naples, and most other south-central
| Italian cities, due to the recent VEI 8 eruption of the
| Campe Flegree caldera complex...".
| PaulDavisThe1st wrote:
| > At least that's guaranteed to be extremely far in the
| future.
|
| a subduction zone quake in the PNW is already overdue
| (they appear to happen regularly with a periodicity of
| 3-600 years). The famous Atlantic article from several
| years ago made it clear that it can be expected at any
| time now.
| hsjsbeebue wrote:
| I wont hold my breath becomes I wont cache my lat/lon.
| aaron695 wrote:
| The Australian tectonic plates move about 7cm a year, if you
| didn't adjust for it they'd be losing 2-5 thousand dollars a year
| as the fence moved in many suburban homes. Of course you'd gain
| it on the other side.
|
| Google needs to be dealing with it constantly, you'd be able to
| observe more errors on Google maps, ie. look at Google directions
| and how often mistakes are made, if it wasn't updated monthly?
| I'd guess yearly is not enough.
|
| Most of this article seems to be about other issues.
| nobodyknowin wrote:
| Yep the monuments on the plates here in USA have actual
| published velocities.
|
| Which means yo can model what the coordinates should be after
| some previous survey and go check them.
|
| Pretty cool!
| the-rc wrote:
| They update the data on a regular basis, like they had to do in
| Japan in 2011 after the tsunami. They even flew planes to capture
| imagery in the immediate aftermath.
| elatto12 wrote:
| It's so crazy, never thought about this before
| croemer wrote:
| Yeah, amazing article
| perotid wrote:
| FWIW, global drift vectors by NASA:
| https://sideshow.jpl.nasa.gov/post/series.html
| dtgriscom wrote:
| ... what's the origin, when the entire surface of the Earth is
| sliding around?
| tkcranny wrote:
| From the article:
|
| > WGS 84 is a global standard tied to no one plate. In
| essence, it is fixed to Earth's deep interior.
|
| Those drift vectors are based on GPS, which the article also
| says relies on WGS 84z
| saalweachter wrote:
| And on fixed surveying markers around the globe.
|
| You'll see them hither and yon, but my favorite is the
| miniature Washington Monument buried next to the real one.
| smolder wrote:
| For anyone curious about the buried mini-monument:
| https://www.atlasobscura.com/places/washington-mini-
| monument
| hank1931 wrote:
| Thank you for turning me on to Atlas Obscura! I
| downloaded the app, and have already marked several
| places I want to visit, and others that I've been to.
| Looking forward to working with it more!
|
| I happened to have been in Thailand recently, and came
| across these statues holding up traffic lights. I found
| it fascinating that a city council would devote resources
| to something like this. I'm looking forward to seeing
| other treasures that Atlas Obscura has.
|
| https://www.atlasobscura.com/places/krabi-traffic-lights
| SketchySeaBeast wrote:
| That's gonna be a trip for archaeologists in a few
| thousand years.
| moffkalast wrote:
| > it is fixed to Earth's deep interior
|
| Which is molten and also not static?
| appletrotter wrote:
| The core of the earth is solid no?
| nobodyknowin wrote:
| It's based on a center of mass point of the earth.
|
| The system is an example of an "ECEF" or Earth Centered
| Earth Fixed system.
|
| Good writeup here -
|
| https://en.m.wikipedia.org/wiki/Earth-centered,_Earth-
| fixed_...
|
| Edit - fixed center statement.
| moffkalast wrote:
| I still don't quite get it. So the center is the
| barycenter of the planet, but that only gives you the
| point, not the axes.
|
| The Z axis seems the most clearly defined as it's just
| aligned to the planet's rotation and the XY plane could
| be defined as just halving that, but the the rotation of
| the XY plane doesn't seem to be well defined. The article
| seems to fix it to the first meridian which is a land
| reference and subject to drift, so it would be
| inaccurate. Or there'd be some reference point in the
| south atlantic where the drift is zero and the rest is
| relative to it?
|
| Further along this line of discussion, it's always been
| immensely puzzling to me how sun-relative solar system
| localization systems handle this sort of thing, since
| while it's possible to locate the sun and a few stars to
| track your absolute rotation and one translational axis,
| where the hell do they get the other two? One reference
| might be Earth signals I suppose, and possibly Jupiter?
| But they are all coplanar so the Z axis resolution from
| triangulation must be complete crap.
| JumpCrisscross wrote:
| The IERS reference median is "the weighted average (in
| the least squares sense) of the reference meridians of
| the hundreds of ground stations contributing to the IERS
| network" [1].
|
| [1]
| https://en.m.wikipedia.org/wiki/IERS_Reference_Meridian
| moffkalast wrote:
| Ah so it's just averaged out, that's a decent solution I
| suppose. But that still makes it fixed to the surface for
| the most part.
| JumpCrisscross wrote:
| > _still makes it fixed to the surface for the most part_
|
| Which makes sense. That's what we're trying to measure.
| You could fix it to a point on the core's surface, but
| what wouldn't be practically useful.
| NooneAtAll3 wrote:
| according to hairy banana theorem, at least one surface point
| won't be sliding sideways
| teruakohatu wrote:
| If you want to see an interesting one in my country:
|
| https://sideshow.jpl.nasa.gov/post/links/KAIK.html
|
| 2016 Kaikoura earthquake:
| https://en.wikipedia.org/wiki/2016_Kaik%C5%8Dura_earthquake
| beefnugs wrote:
| Well up in canada we have 5 year old google street data, and
| nobody even updates business hours on 80k+ cities...
| dhosek wrote:
| I remember having a hand-held Garmin GPS unit back in the '00s
| that I used on a trip to Berkeley from Los Angeles (one bonus was
| that the speedometer in my car didn't work1 so I was able to use
| it as a speedometer for the trip). The location that it showed on
| the map was consistently off by about 50 feet. I wonder now if
| this was a tectonic drift or just an inherent inaccuracy of the
| unit.
|
| [?]
|
| 1. When I think back to that car, it's amazing what a piece of
| junk it was. On the other hand, it _was_ a convertible, so a lot
| of fun although my wife considered it a deathtrap.
| jerzmacow wrote:
| Back in the day GPS was intentionally offset so countries
| couldn't use it for weapons.. well except it's owner of course!
| dns_snek wrote:
| It seems like the intentional degradation didn't work as
| intended in the first place and the inaccuracy could be
| corrected with little effort - at least for someone who had
| the resources to use it for weapons systems, so it only
| affected civilian use cases.
|
| > Because SA affects every GPS receiver in a given area
| almost equally, a fixed station with an accurately known
| position can measure the SA error values and transmit them to
| the local GPS receivers so they may correct their position
| fixes. This is called Differential GPS or DGPS.
|
| https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_.
| ..
| epivosism wrote:
| related: a market summarizing what I know about China's
| intentional map offset laws, specifically on whether Google
| will continue following this (only 4 bettors, not very
| meaningful yet) https://manifold.markets/Ernie/will-google-
| maps-stop-followi...
| gloghmalogh wrote:
| 50 ft seems a little large for plate tectonics , plates move on
| the order of a centimeter per year [1]. (similar to fingernail
| growth!) [1] https://oceanservice.noaa.gov/facts/tectonics.html
| saalweachter wrote:
| I believe North America/ Australia is off by around 10 feet
| since GPS became a thing.
| andrewinardeer wrote:
| Australia's drift was taking into account and standards
| were updated back in 2020. Since 1994 the entire continent
| had moved 1.8 meters north-east.
|
| https://www.icsm.gov.au/gda2020/what-changing-and-why
|
| I'm sure the plate has drifted since the 2020 update and
| another update deployed when appropriate.
| simondotau wrote:
| The natural (or artificial) inaccuracy of GPS tends to present
| as an offset which remains relatively stable for many minutes.
|
| About 10 years ago, I did a lot of canyoning/bushwalking in the
| Blue Mountains just outside of Sydney Australia. I'd have my
| Garmin GPSMAP switched on for the entire journey including the
| car trip. For the 20+ journeys, there would be overlapping
| paths where I was driving the highway through the mountains.
| Except none of the paths overlap. They were all smooth paths
| which matched the curvature of the road, but each one had a
| different offset, typically around 2-5 metres away from the map
| data. (The median of these 20+ paths was highly consistent with
| the map data.)
| wombatpm wrote:
| Owning a junk car is a rite of passage to adulthood hood. You
| learn what to do when a car overheats, how to change a tire,
| replace a fuse, recognize the difference between burning oil
| and radiator fluid, how to jump start a car, and how to call a
| tow truck.
|
| Important life skills
| fy20 wrote:
| The article doesn't mention it, but how are the coordinates of
| property boundaries recorded in South California to take into
| account the drift?
|
| In my relatively tectonically stable country there is a single
| coordinate system for the whole country.
|
| I'd imagine you need to record distance to a local landmark or
| similar? And what happens when there are shifts that end up in
| roads split in two like in Turkey last year?
|
| https://nationalpost.com/news/world/turkey-syria-earthquake-...
| brendanashworth wrote:
| Property boundaries aren't delimited by GPS coordinates, but
| rather a surveyor's instructions on how to locate the boundary
| from a set of known landmarks. In most US states, the Public
| Land Survey System [1] gives "meridians" and "baselines" for
| each region serving as the regional center. Radiating out,
| every 6 miles, is a new "township," with its corners serving as
| the local landmark for property boundaries.
|
| [1] https://en.wikipedia.org/wiki/Public_Land_Survey_System
| topherclay wrote:
| But so that means that you could lose land or gain land if
| enough earth moves and the relative change to the land marks
| is in your favor or not. But it's just not a big enough of a
| deal to do it a different way. I do wonder what the most
| significant occurrence of that is though.
| a2800276 wrote:
| The most significant occurrence is probably land loss due
| to tidal erosion and/or flooding.
| nobodyknowin wrote:
| Surveyors reference monuments on the ground. Since tectonic
| plates tend to move together then so so short lines and
| their corners.
|
| It can get complicated on large tracts or lengths, but
| stuff like rail roads and freeways are composed of many
| small properties anyway.
| mavhc wrote:
| https://www.xyht.com/surveying/more-on-the-datum-epoch/
| Waterluvian wrote:
| Resurvey and publish a new datum. We've been doing it for a long
| time. This is fascinating stuff though because WGS84 predates
| this era of popular web map usage.
| patcon wrote:
| https://archive.is/knK6x
| tucnak wrote:
| > This screenshot represented my position in Google Maps while I
| was standing on my back deck.
|
| In the age of OSINT: not smart.
| ern wrote:
| (2020)
| 082349872349872 wrote:
| Assuming 30cm/pixel and O(75mm)/year plate motion, a several year
| update cycle ought to suffice for visual purposes (how frequently
| does Maps refresh now, anyway?)
|
| https://news.ycombinator.com/item?id=39770836
| epivosism wrote:
| I often think about a scifi story where after X million years,
| somehow familiar humanity survives, and two plates containing
| land with VERY different natural flora and fauna approach each
| other - for example, california, home of many native plant
| defenders, and australia. As they get closer than 50 miles, news
| would start to mention making sure not to cross-transplant
| animals and plants. Under 20 miles, the wind and storms would do
| some work already, but people on both sides may still be
| resisting. But the moment they actually touch for the first time,
| some great treaty may shimmer into enforceable existence,
| changing the future of that whole world.
|
| Or else, they'd just build fences, forbid anyone from living on
| the coast, and maintain this artificial continental boundary
| forever...?
| ffsm8 wrote:
| Humanity won't be alive by that time.
|
| It's a interesting setting to explore in fiction, but has no
| chance of becoming reality.
| alenrozac wrote:
| you must be fun at parties
| Ylpertnodi wrote:
| Aren't parties just a celebration of not being dead yet?
| danparsonson wrote:
| Not being dead yet is well worth celebrating for most
| people though.
| johndunne wrote:
| That's kind of misanthropic, talking in absolute terms. I
| could agree in terms of low possibilities but certainly not
| absolutes. I feel it does a disservice to the few who
| actually come up with genius solutions to problems humanity
| faces and the many who dedicate their lives to solving them
| too.
| ffsm8 wrote:
| Is it, really? With current progress I don't see humanity
| surviving even another 500 yrs, honestly. The main
| intelligent race at that point is likely going to be
| something like a symbiont/cyborg that's part machine. At
| least nothing it'd consider _human_.
|
| Millions of years is a long period of time. Humanity has
| only existed for roughly 200-300k. That's less then 1% of
| the projected time period here.
| Ferret7446 wrote:
| There are two cycles that govern human social change: the
| generational ~10 year cycle and the lifetime ~80 year cycle.
| Each generation adopts new values, and once a generation dies
| their values disappear. Tectonic movement is so slow that I
| think reality will be much more boring than your scifi story.
| The hundred thousand years where the two regions are "close
| enough" is more than enough time for the two peoples to both
| integrate and experience conflict hundreds of times over.
| defrost wrote:
| > after X million years [...] two plates containing land with
| VERY different natural flora and fauna approach each other -
| for example, california [...] and australia.
|
| Yeah, nah - the flora jumped the gap 150 years ago already . .
| .
|
| https://www.independent.com/2011/01/15/how-eucalyptus-came-c...
| tempodox wrote:
| Google cancels the project?
| jraph wrote:
| I wanted to know how it's handled on OpenStreetMap, and here's
| how [1], on a first of April anyway.
|
| If someone knows more on this, don't hesitate to share :-)
|
| [1] https://blog.openstreetmap.org/2017/03/31/osm-plate-
| tectonic...
| tetris11 wrote:
| I was wondering if they were going to apply the correction to
| all objects, but as they hinted at in the post, only objects
| old enough to cause a half meter shift will probably be
| corrected.
|
| Edit: Oh, April Fools. Seemed doable.
| jraph wrote:
| The post is an April Fools, to be clear.
|
| edit: right? It seemed credible, I only noticed the date at
| the end. The part where they would hide the edit from history
| was incredibly shady though, and that's what made me look
| even closer. I would hope they would never do this, if they
| even could. Without this part, the post would not have looked
| like an April Fools, just an actually good idea.
| BlueTemplar wrote:
| I love how that post supposedly ended up being posted on
| the wrong day. XD
| aloer wrote:
| Fun facts I remember from looking into this in university some 9
| years ago:
|
| It's not only the sideways movement of plates that causes a
| shift.
|
| WGS 84 and other reference systems work with an underlying
| ellipsoid reference model. This ellipsoid is chosen to
| approximate the earth surface but it's a simple shape and as such
| can't account well for things like mountains and other
| irregularities in the shape of the earth.
|
| Not only does that mean that your position on a mountain is less
| accurate, it also means that it becomes less accurate over time
| due to mountains growing.
|
| These of course are tiny numbers so compared to a few cm shift of
| the plates it is nothing.
|
| Another fun fact is that the ellipsoid also grows more inaccurate
| over time due to the earth rotating around a fixed axis.
|
| The rotational force slowly causes the earth to flatten at the
| top and bottom (where the poles are) and to widen in the middle.
|
| This too I assume is negligible
|
| Speaking of ellipsoid, today I think it is measured via
| satellite. But in the past things had to be done by hand and were
| more local in nature. There's a lot of history here as well since
| mapping has always been a very important task for governments.
|
| So today in a lot of places a lot of data is still based on
| systems other than wgs84. Either because it's historical data
| (e.g. property boundaries before gps was invented), or because
| they use a more localized reference system including a more
| localized ellipsoid that better matches specific country or state
| needs.
|
| Perhaps one day we will use a big world wide look up table
| instead of a mathematical representation of the earth shape.
|
| What I did at university was to compare a Germany-wide lookup
| grid with the mathematical approach of a Germany-wide reference
| system.
|
| This lookup grid was created by a state agency and was more
| accurate because it could include more localized reference
| systems. In technical terms think of this as a pre calculation
| where each state can choose its most accurate method and then the
| results are put together into a country wide lookup table.
|
| Last fun fact: The result of this comparison showed that the
| difference of a German-wide reference system compared to this
| collection of state-wide reference systems is up to four meters.
|
| Edit: removed word inaccuracy, added difference. It's all
| relative. What it mostly shows is that when working with geo data
| you need to know what source and what target reference systems to
| use. Otherwise things break
| twelvechairs wrote:
| For those looking for a clearer standard it's the International
| Terrestrial Reference System and Frame [0]. The better datums in
| use today are tied to a particular year (epoch) reference frame
| of this.
|
| For instance Australia's GDA2020 [1] is based on ITRF2014 at
| epoch 2020.0. It replaced GDA94 which was based on ITRF1992 at
| epoch 1994.0. The difference is around 1.8 metres
|
| [0]
| https://en.m.wikipedia.org/wiki/International_Terrestrial_Re...
|
| [1] https://www.ga.gov.au/scientific-topics/positioning-
| navigati...
| bgro wrote:
| I'll have to add this to my long list of technical problems when
| people request a teleporting super power.
|
| Some related problems are the planet's location in orbit / the
| solar system's location relative to the entire universe and how
| landscape changes over time (trees/towns/mountains/rivers
| appearing and disappearing).
|
| On another related note, it's worth noting that the ability to
| pause time is a universe-ending super weapon. Even if it worked
| like you intended, you wouldn't be able to use any senses or
| breathe without moving.
|
| Similarly, super speed would cause every human movement to have
| deadly force. You would go insane from the relatively slow action
| of everything operating at standard speed. TV might be hours per
| frame instead of frames per second, with incomprehensible audio
| to match.
| sethammons wrote:
| In the book Treason, the author explores that a tad: a
| character can make a time bubble around them, effectively
| freezing others. At one point, the character is being choked,
| freezes time, opens the assailant's hands and ducks out. When
| the bubble pops, in the frame of reference for the assailant,
| his hands moved too fast, shattering bone and destroying
| tissue. Read that decades ago as a kid and it was illuminating
| on the practical problems of time alteration
___________________________________________________________________
(page generated 2024-03-24 23:01 UTC)