IF you use a PC connected to the internet with an Ethernet wire, then geoclue uses your IP to localize you on a map. The error is about several Km.
For example, if you live in a town, geoclue localizes you in the center of this town, several km away from your home.
If you want a better localization (error = 10 to 20 m)
add a WiFi card or dongle
just activate the Wi-Fi with Networkmanager plasmoid. No need to be connected to Wi-Fi. Just activate.