Hacker News Reader

Comment by sn41 | Hacker News Reader

I have asked this question to a member of the Google maps team, and have not gotten a precise answer. Is there some scheme which can distinguish between floors of a building? This is very useful, for example, store locations inside malls. The LatLong scheme does not seem to be enough. I'm guessing that it will have to be 3D, but I have never heard of a standard location scheme which incorporates this information.

View on HN

Lat, long, elevation. The original and best for delivering an ICBM to your door.

This may work, I should try this. Can current smartphone resolution decide the elevation difference between the first and the second floors of a building?

To some degree, but not quickly and reliably.

They already been doing that for couple of years. Maps already knows which floor I'm on in certain malls if I have the gps+wifi on.

This does rely on an ongoing wifi mapping effort but is the most effective for regular simple smartphones without fancy sensors.

GPS elevation data is pretty poor in my experience. Especially inside buildings.

To reliably triangulate elevation from GPS data you need quite a lot of satellites. Air pressure gives a better signal, but obviously needs to be calibrated for weather etc.

lots of phones have barometric sensors that can be used for more accurate elevation differences. sadly it seems to be a "premium" feature and i can't find it in any phone <300 dollars in price https://ieeexplore.ieee.org/document/6817923

Those sensors you are referring to are not reliable enough to tell elevation accurately. In addition to that, buildings may have different pressure to the outside

i have successfully told the difference between the ground and 3rd floor with a galaxy note 3's barometric sensor(for triggering home routines only when actually at home vs just arriving at the location)

maybe that was just a particularly good sensor...

They are sufficient if you have other phones in the same vicinity at known locations.

If bobs phone is 10 meters higher than alex's phone, and they're in a 2 floor building, bob must be on the top floor and alex on the bottom.

This principle can be used at scale by people like apple and google.

My 2013 Moto X has a barometric sensor. When graphing the raw sensor output, I can see a ~6ft elevation change with little difficulty.

What's wrong with just using floor names, e.g. "First floor"?

Yes, this is the current solution. I am a bit dissatisfied that it is not a "uniform" address scheme. It would be nice if an app can guide you to the exact store on the exact floor based on one location code.

Floors can be weird; I’m not sure how you’d handle a hotel skipping the 13th floor, for instance. Also, are floors 0 indexes or 1 indexed? It therefore probably shouldn’t be built into the protocol.

Or it should be built into the protocol and specify a specific ruleset -- if a country/building follows another, it's up to the user to translate.

In some places it can be -1 or 2 indexed so that a building can have more floors than legally specified.

Also some buildings could have been added to after building and a basement turned into a living area, so -1.

Who determines what is the "first floor"? Last week I had a medical appointment. The doctor's office was on the 6th floor; but, it was 7th floor counting up, as the building's ground floor is the "Lobby."

This is normal in many countries but it's extremely uncommon in theUS, where as you implied the ground floor is typically the "first" (in the numerical sense) floor.

This is a very common numbering scheme in some countries (at least most of Europe) but very uncommon in the US.

The startup I'm involved with has a solution that solves this problem.

Edit: Sorry about the terseness. I decided about half-way through to write a top-level comment that delved more deeply.

In short, our solution is this: http://qalocate.bamsaas.com/wp-content/uploads/2018/12/QA-Lo...

The AliLocator is flexible enough that whole structures can be sub-divided by any arbitrary criteria, with floor as potentially one of many. Since the AliLocator itself would be a bit awkward to use, you'd just want to create an LNS entry that then pointed to it.

right, I can't see anything about distinguishing floors and doors. I'm pretty sure there are large amounts of people who need a floor and door added to their identifier in order to - what was it again "receive deliveries, access emergency services, register to vote – and more."

Reply on news.ycombinator.com