It uses the known position of WiFi access points that are visible to your desktop PC to triangulate your position.
But this answer leads to another question:
How does Google know the geographical position of WiFi access points?
Well, they certainly use different sources, but first let me clarify that all of them continuously feed a system that consolidates all the data and creates the geolocation map of the WiFi networks. This map is the one that your PC consults to know your location.
Here are some well-known sources:
Android devices: When you activate the GPS of an Android device, it has valuable information. Geographic position and accuracy plus list of WiFi access points and cell towers in range (including signal strength). Under these conditions, the Android team sends anonymous reports (with no information about the user) to Google Maps. This information is added to the system.
GOOGLE'S FLEET: The Google Fleet, the same one that takes Google Street View photographs, as it travels through cities and roads, reveals WiFi access points and feeds the system.
They may have other sources, such as laptops that include a GPS receiver. These can also contribute information to the system.
Grades:
If you change the name of a WiFi access point and add the suffix "_nomap" to it (eg it is called GermanWifi and you rename it GermanWiFi_nomap ) this access point is removed from the map and is not used by google.
This practice is not exclusive to Google. Apple and Microsoft do the same with their respective mobile platforms.
The simple answer is:
But this answer leads to another question:
Well, they certainly use different sources, but first let me clarify that all of them continuously feed a system that consolidates all the data and creates the geolocation map of the WiFi networks. This map is the one that your PC consults to know your location.
Here are some well-known sources:
Android devices: When you activate the GPS of an Android device, it has valuable information. Geographic position and accuracy plus list of WiFi access points and cell towers in range (including signal strength). Under these conditions, the Android team sends anonymous reports (with no information about the user) to Google Maps. This information is added to the system.
GOOGLE'S FLEET: The Google Fleet, the same one that takes Google Street View photographs, as it travels through cities and roads, reveals WiFi access points and feeds the system.
They may have other sources, such as laptops that include a GPS receiver. These can also contribute information to the system.
Grades:
If you change the name of a WiFi access point and add the suffix "_nomap" to it (eg it is called GermanWifi and you rename it GermanWiFi_nomap ) this access point is removed from the map and is not used by google.
This practice is not exclusive to Google. Apple and Microsoft do the same with their respective mobile platforms.