Broadband users usually deploy a wireless router to connect phones, tablets, laptops and a myriad of other devices. By default these routers broadcast an SSID (service set identifier). A popular scanner WiGLE (Wireless Geographic Logging Engine) is available for Android (Google Play) but not Apple (ask them). People using WiGLE have logged over 5,000,000,000 observations of over 360,000,000 networks and almost 800,000 cell towers.
Navigating wigle.net requires a little practice. You can start out with a street address which will be standardized (with any luck you will see an appropriate suggestion) and then zoom out to get a grasp on the area and then zoom in to get SSIDs. You may have to recenter the map to get the area you want. Red dots are the most common and indicate a weak router, green - stronger.
Devices note when an SSID first appears and when they disappear. The GPS in the device locates two points which define a chord (line). The first guess is the midpoint of that chord. As additional samples are gathered from devices taking different paths, the location guess improves. Even at its best, these locations can be several hundred feet off. This also explains why many points are located on highways.
If you find no dots in your area, you can fire up the WiGLE Android app and drive around your neighborhood. When your drive is complete (or when you get back to a wireless signal for your phone) you can upload your observations to everyone's benefit.
The default SSIDs frequently reveal the manufacturer of the router or the ISP providing the router. People who deploy their own router often choose an SSID related to their interests.