Do you have a Wi-Fi Router on your local Network? If you do, you may get better location data by turning on Wi-Fi and using the gear below the list of Interfaces to "Set Service Order" to make Wi-Fi SECOND (with your regular Ethernet first).
This will give you an additional Wi-Fi address, but it will also allow your Mac to figure out exactly where you are.
My Story: I live in the woods, just a little too far off the street for drivers or neighbors to "see" my Wi-Fi signals. For months, None of the devices knew the proper location. No one in the house had an iPhone.
Then we had a party, and invited lots of friends, many of whom had iPhones, and they were here for hours. After they left, I noticed that my computers now knew EXACTLY where each Router was, and they were separated in space by about the actual distances involved.
The iPhones had reported the network locations of each Router (I have three), and since there were multiple reports, it was corroborated data and was entered in some database on the web. So my Routers "knew where they were" indirectly.