Positioning systems may be used to determine the location of computing devices in space. Described herein are systems, methods, and computer readable mediums for storing information determined to be reliable that is used to determine the location of a computing device. In some implementations, the system determines that a scan list is reliable based on factors such as characteristics associated with the type of device that generated the scan list, or based on the amount of times that the information in the scan list was detected over a period of time.