There are lots of different ways a company like MaxMind can try to figure out where an IP address is located. It can “war-drive,” sending cars around the U.S. looking for open wifi networks, getting those networks’ IP addresses, and recording their physical locations. It can gather information via apps on smartphones that note the GPS coordinates of the phone when it takes on a new IP address. It can look at which company owns an IP address, and then make an assumption that the IP address is linked to that company’s office.

    But IP mapping isn’t an exact science. At its most precise, an IP address can be mapped to a house. (You can try to map your own IP address here.) At its least precise, it can be mapped only to a country. In order to deal with that imprecision, MaxMind decided to set default locations at the city, state and country level for when it knows only roughly where the IP address lives. If it knows only that an IP address is somewhere in the U.S., and can’t figure out anything more about where it is, it will point to the center of the country.


This has been making the rounds, but I think something is missing from the story. Every geocoding API will tell you how big a grain of salt you should take its response with. I have never used it, I only ever need to geocode addresses, but it looks like MaxMind returns a sequence of objects representing the country, county, city, ... down to the most specific entity they could find, and also a measure of their confidence and a radius the real location should be expected to fall within. I can see going into a project naively expecting that when you get a latitude and longitude, it represents an actual point on the earth, but if you RTFM enough to know how to use the thing at all you should get the hint, and even if you don't you should notice you're getting the same point back for a surprising number of distinct queries. I have a hard time buying that many people being that incompetent.

posted by kleinbl00: 1010 days ago