Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Satellites auto detect buildings in OpenStreetMap

medium.com

Post reply on HN
Print view View original

11–20 of 35 posts

Re: Satellites auto detect buildings in OpenStreetMap

#11

Post by andrewljohnson »

manarth wrote: post #10
andrewljohnson wrote: post #4

This has been heating up. Here's the seminal paper that kicked off the Cambrian Explosion: https://www.cs.toronto.edu/~vmnih/docs/Mnih_Volodymyr_PhD_Th... And I saw two presentations about this at State of the Map US. * Anand Thakker of Development Seed had a cool live demo: https://www.youtube.com/watch?v=BftllmqXSpA&list=PLqjPa29lMi... * Facebook mapped a bunch of roads in Egypt, and has an ongoing effort. Facebook…

> "There is starting to be a debate in the OSM community about allowing robot edits into the map" What do you think about a hybrid: bot detects and recommends changes, which are then queued or tagged for human verification? I've been looking at scuba data in the OSM dataset, and there are a number of bot-added entries, with a tag "verified": "no, please check and del this tag" (e.g. Maaya Thila dive site [1]). [1] ht…

That's the status quo.

I'm in favor of a regime where there is a benchmark for the recall and precision rates for the automated analysis, and anything that hits the benchmarks is acceptable. I don't regard this as a philosophical matter - let's accept any bot analysis that hits a certain threshold.

1) We can certainly set the threshold above the TIGER import in the US, which most people agree is positive, but very crufty.

2) It's the developing parts of the world that need automated road creation the most. The opposition seems to emanate from rich, European nations.

Re: Satellites auto detect buildings in OpenStreetMap

#12

Post by reportingsjr »

andrewljohnson wrote: post #4

This has been heating up. Here's the seminal paper that kicked off the Cambrian Explosion: https://www.cs.toronto.edu/~vmnih/docs/Mnih_Volodymyr_PhD_Th... And I saw two presentations about this at State of the Map US. * Anand Thakker of Development Seed had a cool live demo: https://www.youtube.com/watch?v=BftllmqXSpA&list=PLqjPa29lMi... * Facebook mapped a bunch of roads in Egypt, and has an ongoing effort. Facebook…

I'm really glad to see all of this going on! I did a little bit of building outlining in OSM and stopped when I realized that it would probably be automated within the next few years.

Re: Satellites auto detect buildings in OpenStreetMap

#14

Post by lucb1e »

> The green buildings are existing structures captured in OpenStreetMap. The red buildings are the ones we detected as missing from the map.

And which color is existing structures not identified by the software? Because that would be a very quick and easy way to spot how well it's actually performing.

Re: Satellites auto detect buildings in OpenStreetMap

#15

Post by lucb1e »

andrewljohnson wrote: post #11
manarth wrote: post #10

Earlier quoted context omitted.

> "There is starting to be a debate in the OSM community about allowing robot edits into the map" What do you think about a hybrid: bot detects and recommends changes, which are then queued or tagged for human verification? I've been looking at scuba data in the OSM dataset, and there are a number of bot-added entries, with a tag "verified": "no, please check and del this tag" (e.g. Maaya Thila dive site [1]). [1] ht…

That's the status quo. I'm in favor of a regime where there is a benchmark for the recall and precision rates for the automated analysis, and anything that hits the benchmarks is acceptable. I don't regard this as a philosophical matter - let's accept any bot analysis that hits a certain threshold. 1) We can certainly set the threshold above the TIGER import in the US, which most people agree is positive, but very cr…

Robot edits are great when they add data. When modifying or removing work that humans did, I'm much more hesitant. This is probably why there's opposition from "rich, European nations": the developing world has little data that anything could go wrong with.

I'm not necessarily pro autonomous robots unless they either hit very high benchmarks, or it's purely for initial groundwork (or improving on previous bots' work). I totally see how it could be great for unmapped places where it could add grass/forest areas, houses, roads, rivers, etc. but tampering with existing data with no review queue (if not an approval queue, at least post-editing review)... I'm hesitant.

Re: Satellites auto detect buildings in OpenStreetMap

#16

Post by protomikron »

This is an interesting area and the most important recent change is the opening of the data. More and more municipalities provide web services where you can download high-quality imagery, e.g. have a look at https://www.wien.gv.at/ma41datenviewer/public/ in the left menu you can select "Luftaufnahmen" (aerial imagery) or DOM (Digitales Oberflaechenmodell == Digital Surface Model) and the resolution is quite high (unfortunately the imagery is watermark-raped, but most training methods are robust against that kind of errors). One might think aerial imagery is not a problem, as we have Google Maps, Bing, etc., but you reach there (free) API limits quite fast, if the goal is to get bulk data to train classifiers.

In particular laser data is a game changer and makes building footprint detection much simpler (you can make pretty training masks from the provided vector layers and train e.g. a NN for segmentation). Current state-of-the art in building and street detection from photos only is around 85% to 95%, which is quite high, but a bit too low for fully automatic usage in e.g. urban development or environmental engineering. In particular there are images where it is nearly impossible to distinguish the roof from the nearby place, if the roof is not enclosed by a green area or a garden.

At the moment classifications/segmentations are polished by humans (and providing accurate (satellite or aerial) imagery classification is a big business), but DSM data is so good, that it makes fully automatic approaches feasible and I would say one could reach ~99% there.

Re: Satellites auto detect buildings in OpenStreetMap

#17

Post by andrewljohnson »

lucb1e wrote: post #15
andrewljohnson wrote: post #11

Earlier quoted context omitted.

That's the status quo. I'm in favor of a regime where there is a benchmark for the recall and precision rates for the automated analysis, and anything that hits the benchmarks is acceptable. I don't regard this as a philosophical matter - let's accept any bot analysis that hits a certain threshold. 1) We can certainly set the threshold above the TIGER import in the US, which most people agree is positive, but very cr…

Robot edits are great when they add data. When modifying or removing work that humans did, I'm much more hesitant. This is probably why there's opposition from "rich, European nations": the developing world has little data that anything could go wrong with. I'm not necessarily pro autonomous robots unless they either hit very high benchmarks, or it's purely for initial groundwork (or improving on previous bots' work)…

Again, I wouldn't be philosophical about "When modifying or removing work that humans did, I'm much more hesitant."

If a robotic system can demonstrate some high bar of precision in modifying human updates, then let the edits happen. If a human mapped a road, then that road changed places or perhaps changed from being two-way to one-way and a robot can detect that reliably, let the robot edit.

That said, I don't think "robots changing human edits" is where the robots shine. Most human edits will be good, unless the data later changes. I agree that the low hanging fruit is 1) mapping new features, 2) cleaning up imports like TIGER, 3) providing "lint" type tools to give human editors feedback if their new edit might be wrong.

Re: Satellites auto detect buildings in OpenStreetMap

#18

Post by maxerickson »

andrewljohnson wrote: post #17
lucb1e wrote: post #15

Earlier quoted context omitted.

Robot edits are great when they add data. When modifying or removing work that humans did, I'm much more hesitant. This is probably why there's opposition from "rich, European nations": the developing world has little data that anything could go wrong with. I'm not necessarily pro autonomous robots unless they either hit very high benchmarks, or it's purely for initial groundwork (or improving on previous bots' work)…

Again, I wouldn't be philosophical about "When modifying or removing work that humans did, I'm much more hesitant." If a robotic system can demonstrate some high bar of precision in modifying human updates, then let the edits happen. If a human mapped a road, then that road changed places or perhaps changed from being two-way to one-way and a robot can detect that reliably, let the robot edit. That said, I don't thin…

I'm curious how the lint aspect of DeepOSM will work in areas that have less room for improvement than the areas I looked at in Delaware and Maine. In those areas, the imported TIGER data is poor enough that a road by road analysis is overkill. The DeepOSM output flagged most of the roads.

Given the capacity to run it, an interesting analysis would be an evaluation of the entire United States, maybe grouped by county or so. Then people in well mapped cities looking for a project could improve the worst county in their state, or the worst county in the US, etc.

Re: Satellites auto detect buildings in OpenStreetMap

#19

Post by Doctor_Fegg »

andrewljohnson wrote: post #4

This has been heating up. Here's the seminal paper that kicked off the Cambrian Explosion: https://www.cs.toronto.edu/~vmnih/docs/Mnih_Volodymyr_PhD_Th... And I saw two presentations about this at State of the Map US. * Anand Thakker of Development Seed had a cool live demo: https://www.youtube.com/watch?v=BftllmqXSpA&list=PLqjPa29lMi... * Facebook mapped a bunch of roads in Egypt, and has an ongoing effort. Facebook…

> Facebook mapped a bunch of roads in Egypt, and has an ongoing effort

Worth noting that the Facebook robomapping was of extremely poor quality (it actually managed to completely break the OSRM router, which is quite some achievement) and has now been reverted for that reason.

Re: Satellites auto detect buildings in OpenStreetMap

#20

Post by autokad »

lucb1e wrote: post #14

> The green buildings are existing structures captured in OpenStreetMap. The red buildings are the ones we detected as missing from the map. And which color is existing structures not identified by the software? Because that would be a very quick and easy way to spot how well it's actually performing.

or which red buildings aren't buildings. It'd be nice to verify on a city such as Philadelphia that has an open parcel layer, but then again cities with parcel layers are probably well mapped out in OSM
Post reply on HN