through the api https://developers.google.com/maps/documentation/geolocation/intro https://developers.google.com/maps/documentation/geolocation... there are a

through the api https://developers.google.com/maps/documentation/geolocation/intro https://developers.google.com/maps/documentation/geolocation... there are also many open source wifi location databases that can be downloaded and queried locally devices listening to ssid broadcasts for this purpose are common at grocery stores, malls, political protests, and more