gps to be with the map use, first of all you want to download the map (better have Baidu Maps, Google Maps, high moral map, navigation, dogs Kay Rucker), if you want the phone when the navigator to use it you on the use of Kay Rucker maps, this comparison professional, but larger than the data of the map pack reached 2.75GB, if you just use it in the urban area with several other maps, offline packet is relatively small, there is the need to consume a certain flow. Lastly, I hope the landlord told me to JIAYU G4 phone screen resolution, Kay Rucker map resolution and a small version of the resolution. If you need to download can give you the address.