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Reverse geocoding is hard

shkspr.mobi

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Re: Reverse geocoding is hard

#71

Post by 867-5309 »

meindnoch wrote: post #60
AlotOfReading wrote: post #22

Earlier quoted context omitted.

GPS coordinates actually account for the motion of the Earth's tectonic plates. The problem is that it's a highly approximate model that doesn't accurately reflect areas like Australia very well. There's a great visualizer of the coordinate velocity from the Earthscope team: https://www.unavco.org/software/visualization/GPS-Velocity-V...

>GPS coordinates actually account for the motion of the Earth's tectonic plates. What?

accounts for (something), phrasal verb meaning "considers; incorporates; takes on board" as opposed to the more obvious "gives rise to; is responsible for". I had to read twice too

Re: Reverse geocoding is hard

#72

Post by robin_reala »

1970-01-01 wrote: post #70

>But how do you go from a string of digits to something human readable? Hasn't What3Words already solved this?

It’s a closed and proprietary system that contains locations like master.beats.slave near Brooklyn and whites.power.life in Washington (to pick just a couple of examples off the top of my head). If your only requirement is “human readable” and assumes the human knows how to read and pronounce English words then I guess it kinda does.

Re: Reverse geocoding is hard

#74

Post by 1970-01-01 »

robin_reala wrote: post #72
1970-01-01 wrote: post #70

>But how do you go from a string of digits to something human readable? Hasn't What3Words already solved this?

It’s a closed and proprietary system that contains locations like master.beats.slave near Brooklyn and whites.power.life in Washington (to pick just a couple of examples off the top of my head). If your only requirement is “human readable” and assumes the human knows how to read and pronounce English words then I guess it kinda does.

>and assumes the human knows how to read and pronounce English words

I hit a dozen random benches. If these are the low requirements, W3W would and does do a great job for openbenches: https://openbenches.org/bench/random/

Re: Reverse geocoding is hard

#75

Post by modeless »

andrew_eu wrote: post #53

I have a memorable reverse geocoding story. I was working with a team that was wrapping up a period of many different projects (including a reverse geocoding service) and adopting one major system to design and maintain. The handover was set to be after the new year holidays and the receiving teams had their own exciting rewrites planned. I was on call the last week of the year and got an alert that sales were halted…

Wow, I had no idea that Taiwan controlled an island less than three miles from mainland China, essentially surrounded by China in a bay. (The main island is 80+ miles away.) I'm really surprised China has allowed that for 80 years. Unsurprisingly, the beach looks like this: https://www.google.com/maps/place/Shuang+Kou+Zhan+Dou+Cun/@2...

Also interesting that there's a Japanese island only 60 miles from Taiwan on the other side. I guess claims to small Pacific islands have been weird for a long time.

Re: Reverse geocoding is hard

#76

Post by RainyDayTmrw »

Dachande663 wrote: post #13

Fun fact that was dredged up because the author mentions Australia: GPS points change. Their example coordinates give 6 decimal places, accurate to about 10-15cm. Australia a few years back shifted all locations 1.8m because of continental drift they’re moving north at ~7cm/year). So even storing coordinates as a source of truth can be hazardous. We had to move several thousand points for a client when this happened.

This is one of many reasons why property surveying records use so many seemingly obscure or redundant points of reference. In case anyone wonders why modern property surveying isn't only recording lots of GPS coordinates.

Re: Reverse geocoding is hard

#77

Post by mootothemax »

sinuhe69 wrote: post #26

Not my area of expertise, but is this not a form of perfectionist problem? I mean, most places have a clear and simple address. For the rest, either a human can solve it, or we can make a few examples and let an AI do the work. We can go back to them later and revise them if we need to. Addresses don't change often, so I think things can stay the same for a long time. Except for emergency dispatch and a few high-prof…

> most places have a clear and simple address

That depends on your definition of "clear and simple" and "address" :) While a lot boils down to use case - are you trying to navigate somewhere, or link a string to an address? - even figuring out what is an address can be hard work. Is an address the entrance to a building? Or a building that accepts postal deliveries? Is the "shell" of a building that contains a bunch of flats/apartments but doesn't itself have a postal delivery point or bills registered directly to it an address? How about the address the a location was known as 1 year ago? 2 years ago? 10 years ago?

Park and other public spaces can be fun; they may have many local names that are completely different to the "official" name - and it's a big "if" whether an official name exists at all. Heck, most _roads_ have a bunch of official names that are anything but the names people refer to them as. I have a screaming obsession with the road directly in front of Buckingham Palace that, despite what you see on Google Maps, is registered as "unnamed road" in all of the official sources.

> Addresses don't change often

At the individual level, perhaps. In aggregate? Addresses change all the time, sometimes unrecognisably so. City and town boundaries are forever expanding and contracting, and the borders between countries are hardly static either (and if you're ever near the Netherlands / Belgium border, make a quick trip to Baarle-Hertog and enjoy the full madness). Thanks to intercontinental relative movement, the coordinates we log against locations have a limited shelf life too. All of the things I used to think were certain...

If someone hasn't done "faleshoods programmers believe about addresses," I think its time might be now!

Edit: answering myself with https://www.mjt.me.uk/posts/falsehoods-programmers-believe-a...

Re: Reverse geocoding is hard

#78

Post by mootothemax »

edent wrote: post #15
andrewaylett wrote: post #5

It's a lot more expensive, but measuring navigation distance rather than straight line distance would avoid the "river" issue. Although depending on the routing engine and dataset it might well introduce more issues where points can be really close on foot but the only known route is a driving route.

If you know of an API which does navigation distance to POI, I'd love to hear about it!

You can self-host or run locally Valhalla (https://github.com/valhalla/valhalla), reading in data from OSM as a starting point.

(For my purposes, I went with local running, generating walking-distance isochrones across pretty much well the entire UK)

Re: Reverse geocoding is hard

#79

Post by anotherevan »

pavel_lishin wrote: post #35
Dachande663 wrote: post #13

Fun fact that was dredged up because the author mentions Australia: GPS points change. Their example coordinates give 6 decimal places, accurate to about 10-15cm. Australia a few years back shifted all locations 1.8m because of continental drift they’re moving north at ~7cm/year). So even storing coordinates as a source of truth can be hazardous. We had to move several thousand points for a client when this happened.

Damn! 7cm per year feels blazing fast when you consider the fact that it's a whole continent.

We're coming for you!

Re: Reverse geocoding is hard

#80

Post by mootothemax »

robin_reala wrote: post #72
1970-01-01 wrote: post #70

>But how do you go from a string of digits to something human readable? Hasn't What3Words already solved this?

It’s a closed and proprietary system that contains locations like master.beats.slave near Brooklyn and whites.power.life in Washington (to pick just a couple of examples off the top of my head). If your only requirement is “human readable” and assumes the human knows how to read and pronounce English words then I guess it kinda does.

Yeesh slave.trade.market too!
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