Geolocating public nodes in the Internet infrastructure is hard. No single approach has been proven successful, nor is any dataset (publicly) available that is accurate enough to be considered reliable.
The RIPE NCC has now launched a new tool, that targets this problem. The tool consists of a web interface and an API. The tool tries to infer the location by combining multiple automated methods and coming up with an overall preferred geo-location for an IP address. One such method uses latency of ping measurements from RIPE Atlas probes to assess the actual distance of the IP address to these probes.
OpenIPmap presents the overall results of the engines and asks for input from the user. Thus a crowdsourced dataset arises that combines both the power of computational based and human analysis.