That might work in big countries like the US, but in western Europe it's basically impossible to tell whether a connexion originates from London, Paris, Brussels or Amsterdam just by hop count or latency.
Even just jitter in router response time is already higher than the difference in latency due to speed of light between those locations. And just France is large enough that a connexion to some IP in France might legitimately travel further or not compared to a connexion to some other country, from basically any vantage point you might be looking from, and might or might not round-trip through Paris, adding potentially up to 1500 km of uncertainty in the path.
Identifying the interchanges the packets go through can help though, but not as much for residential ISPs.
Even just jitter in router response time is already higher than the difference in latency due to speed of light between those locations. And just France is large enough that a connexion to some IP in France might legitimately travel further or not compared to a connexion to some other country, from basically any vantage point you might be looking from, and might or might not round-trip through Paris, adding potentially up to 1500 km of uncertainty in the path.
Identifying the interchanges the packets go through can help though, but not as much for residential ISPs.