[sdfhbdf]

IPV4 geolocation is based on maintained databases (e.g. Ma Mind) that usually are city or street accurate.

The popular rhetoric that having an IP is having the location is most often wrong unless Your users have static IPs registered to them. The way law enforcement does it is by subpoening the owner of the IP of pointing to the user associated with the IP at specific time but that still is prone to errors because of NATs - many distinct clients behind a single address.

All in all fingerprinting is using IPs pretty rarely nowadays.

[est31]

If other devices in your network send data to Google, the network is uniquely identifiable by Google, no matter what individual devices of guests etc. do.

[kortilla]

CGNAT means sometimes an IP just identifies an entire ISP and nothing more.

[tpmx]

The combination of occasional GPS/Wifi location data and continuous IP data is pretty powerful though.

[inquirerofsorts]

There's a setting hidden away in android allowing apps to scan local wifi/bluetooth networks even when wifi is turned "off". Enabled by default of course.

[rainingcatndogs]

What settings is that?

[klvino]

Settings > Location > Improve Accuracy

2 settings, one for Wi-Fi scanning and one for Bluetooth

[tpmx]

Security & Location -> Privacy -> Location -> Scanning

(Supposedly; I don't own an up-to-date Android device.)

[ecabuk]

I bet Google can do better job than the MaxMind but even the city accuracy isn’t that enough? I think it is enough to effect your localized ads.