Fingerprinting is a technique that records vectors of received power from several transmitters, and later matches these to a new measurement to position the new user. This paper examines data used in earlier fingerprinting experiments in a WiFi network to characterize the eventual positioning errors. The implied relationship between real distance and `vector` distance between fingerprints is tested and found to be poor. However, because fingerprinting algorithms use nearest neighbour techniques, these nearby fingerprints were examined and found to be better behaved. © 2008 IEEE.