Computer-implemented systems and computer-readable media for generating distance bands on a map to identify areas of outbound roaming on a wireless network are disclosed. A roaming-network event record listing roaming events for subscribers of a home network is received. A home-network event record listing network events on a home network is also received. The two records are correlated to identify roaming events and network events having matching caller identifiers and time stamps within a predetermined range. Location data of a network event is adopted as location data for a matching roaming event. A home-network wireless-communications antenna having a service area in which a concentration of roaming events have occurred is identified. The distance of the roaming events from the antenna is determined and distance bands corresponding to that distance are plotted on a map to aid in identifying locations at which outbound roaming has occurred.