Geo location to IP mapping

Here is a tech report with a survey on geolocation and evasion techniques:

Tao Wan

This document seems to miss one other fairly common way in which geolocation fails: VPN. Whether a single user VPN session in which the user's laptop obtains an IP address from the VPN gateway, or a subnet extended out across a VPN to a remote office, the user(s) will appear to be at the location of the VPN concentrator. While ping latency, if even transported over the VPN, may show a greater distance than other IP addresses in teh neighborhood, there is no clear way to know why that latency is higher. It's odd this was omitted.