Generally, a 4-hour travel code will show the history of the local stay, which means that if you stay for more than 4 hours, the travel code will show a track.

Generally just passing through or a short stay is not a footprint, and will not be pulled to the quarantine and other anti-epidemic measures, before traveling to look carefully at the local epidemiological situation.

"Communication big data itinerary card" analyzes the "cell phone signaling data", through the user's cell phone is located in the base station location to obtain, signaling data collection, transmission and processing automation, there is a strict security and privacy protection mechanism, query results are available in real time, convenient and fast.

The data of the "Communications Big Data Trip Card" can be used nationwide, which can truly achieve comprehensive coverage of the whole country, and can also be used to inquire about the international trips of one's domestic cell phone number. These will provide scientific and accurate technical support for epidemic prevention and control, resumption of work and production, road access, and entry and exit under the premise of ensuring user information security.

The data source of the location query service provided by the trip card is "cell phone signaling data", which is obtained through the location of the base station where the user's cell phone is located. In order to ensure continuous communication, realize coverage without blind area and provide better communication service quality, the signals of two base stations at the junction of administrative divisions may be cross-covered, resulting in deviation of the results.

This is possible if the user lives close to the city boundary, or if he/she drives long distances or takes the train.