Tell HN: Google Maps is again requiring wi-fi scanning to enable navigation | Hacker News Reader

Tell HN: Google Maps is again requiring wi-fi scanning to enable navigation

40 pointscausality019 comments

As far as I can tell it's an exact copy of the behavior they exhibited last year and discussed in this thread: https://news.ycombinator.com/item?id=30167865

Personally when I turn off my Wi-Fi I want it to be off, period.

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After reading that thread, why would you be worried about Google having things like your surrounding WiFi SSIDs and not be worried about them having your GPS coordinates? This data collection feels like it's only done to contribute to and maintain their A-GPS database and not to actually track users for ads, since that can be done with just GPS.

I don't care about data collection. I care that when I turn something off it stays the hell off, not just lying to me about being off when it wakes up every ten seconds and wastes some of my battery wardriving for a trillion dollar company.

Not advocating for or against Google but GPS is extremely power intensive --> battery life. AGPS (and PGPS) is better but still power hungry and difficult due to antenna inefficiencies and extremely small signal levels. Wifi is much better in terms of power envelope and is ubiquitous in urban environments where GPS is challenging. Dead reckoning is much better than it used to be but is difficult because IMU noise is integrated over time and only gives relative location not absolute.

Which is fine when I'm using maps. Google wants to activate my wi-fi for its own purposes 24/7 even when I have it turned off.

Does anyone know what Maps actually uses Wifi for? I read it's to increase accuracy but is it really that common that GPS accuracy isn't precise enough? I get that there are GPS blindspots e.g. tunnels, downtown "canyons" but Maps is pretty smart at interpolating one's location by using accelerometer data.

I think those "downtown canyons" are likely to be the places where wifi information helps the most, so that would be my guess.

I don't know, but I imagine accelerometers work ok for cars on roads, but less so for meandering pedestrians in alleys and semi-enclosed shopping plazas.

Your phone has a tiny antenna, unless you live out in the country you won’t have good sky view most of the time, and it takes time to get a fix. Most people open their phone and expect to know where they are within a few seconds.

For one, it can speed up finding your location if GPS is cold. Maps will start zeroing in by using wifi while GPS is heating up and then it gets the precise location from gps when it is available.

Googlers correct me on this, but from observation, that's how it seems to work.

It is exactly that. Increased accuracy. Think of driving on a tight street, buildings left and right and buildings with 10-15 floors. It will take forever for the GPS to get "enough" to be able to give you an accurate reading fast. But if 20 cars have passed in various speeds, you will get an estimate much faster.

I have actually tested this. It would take 45sec with just GPS, but under 7sec with WiFi.

Knowing Google's ethics (haha) they will definitely use this data also to advertise services to the people living there, as "now" they know exactly where you live and thus may push more relevant ads instead of a random store 500km away.

Getting a GPS fix from scratch (aka a cold start, where the receiver doesn't know anything in advance) takes minutes.

Even if you take advantage of tricks like out-of-band time, almanac, and ephemeris data, it can still take in the neighborhood of 10 seconds to get a fix. I imagine wifi is also less susceptible to issues that plague GPS like multipath and urban canyons

(a) People walking around near your house with Android phones are constantly Wi-Fi scanning their environment, correlate Wi-Fi SSIDs and MAC addresses with GPS locations, and sending this info to Google

(b) When you or anyone else don't have a GPS signal because you're indoors, Google can run a Wi-Fi scan and geolocate you indoors from (a)

Also, s/Google/Apple/, s/Google/Mozilla/, they all do the same thing.

You can even run a Wi-Fi scan yourself with "sudo iwlist scanning", put the data in the appropriate format, and send it to Google's API [1] or Mozilla's API [2] for geolocation.

[1] https://developers.google.com/maps/documentation/geolocation...

[2] https://ichnaea.readthedocs.io/en/latest/api/geolocate.html#...

How did it manifest? I just turned off wifi and wifi scanning and navigation still seems to work fine for me. No permissions prompt at all, though it's hard to tell from the linked post exactly what was happening at the time.

Tapping a location icon on the map or using Assistant works as expected but trying to use a shortcut or one of your hotbar locations like Home or Work or trying to re-center the map gets me a demand popup and a refusal to navigate or show directions, with a "Can't apply some route options" if I try again. If it's like last year the wifi scanning demand will expand to more and more of the map functionality over time.

Try clearing app data. Google Maps recently started going crazy for me, it either ignored compass or it was always showing its precision as low (therefore not using it), it only wanted to find real world directions by scanning with camera (which doesn't work outside cities). Today it wanted me to enable high precision and scanning networks even I have them on.

I decided to clear the app data, everything is in the cloud anyway and boom, all the issues are magically gone.

This feature drives me nuts. I thought AGPS triangulation was good enough for gps canyons. Why do they need WiFi locations?

I can't find anything on AGPG triangulation. What is that?

Sorry meant AGPS. The service use by 911 to find you when you don't have line of sight to the GPS satellites.

@dang Why was this an appropriate topic eighteen months ago but it isn't now?

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