Due to the Internet policy of China, certain websites and applications are not accessible from the mainland, which includes those very commonly used in the west (Facebook, Instagram, Twitter, Google, Skype and more). Some travellers have been able to gain access to those via a VPN service (installed prior to arrival in China).
Make sure you comply with local laws and regulations when deciding on whether or not to employ a VPN, and which one to choose (if you do, only use those explicitly allowed by the Chinese government, and only use them for authorised purposes to avoid any trouble). There have been reports of foreigners in China getting their cell service cut off in response to unauthorised use of VPN being detected; restoring cell service required a trip to the local police station where contents of the device were investigated and certain apps removed.
Giving that Google is banned in China, Google Maps might not be the most accurate and reliable source of information. Some local apps such as Baidu Maps and AutoNavi tend to work better than Google Maps.