MOBILE COMMUNICATION UNIT

摘要

PROBLEM TO BE SOLVED: To provide an excellent mobile communication unit in which storage capacity can be utilized effectively while suppressing communication cost by storing map data having a high use frequency and deleting map data having a low use frequency. SOLUTION: A control unit 11 mounted in a navigation system 10 displays rough map data in a database 16 on the screen of an output unit 12 and also displays detailed map data on the screen of the output unit 12 by requesting a base station 100 to transfer required detailed map data through a communication unit 15 according to input operation from an input unit 13. Furthermore, the control unit 11 stores corresponding use frequency in a hard disc 17 such that it can be reused and secures the storage capacity of the hard disc 17 by deleting detailed map data having a low use frequency when the residual capacity thereof reaches a set value.