The big data can be checked by people who don't use cell phones. The trip code data is from the database of the National Big Data Center and is related to everyone's ID information.

Data sources come mainly from train tickets, bus ticket information, skynet surveillance data, cell phone location data, cell phone payment data, etc. Mobile phone is only one of the data sources, there are many other sources, so do not bring a cell phone trip is recorded.

Big data, IT industry terminology, refers to a collection of data that cannot be captured, managed and processed within a certain timeframe using conventional software tools, and is a massive, high-growth, and diverse information asset that requires a new processing model to have stronger decision-making, insight discovery, and process optimization capabilities.