Chunyun in the ticket data

As well as the big data acquired from changing locations, ticket buying information is another important source.

On January 9 2014, total visits to the train ticket purchase website 12306 and its mobile client numbered 8.4 billion. That was the day when people began to buy tickets for the day before New Year's Eve – the ones which are most in demand. 8.4 billion visits is the equivalent of every person in China visiting the website more than 6 times in the day. The website received 240 thousand clicks every second. If you were one second late when trying to buy your tickets online, you would fall behind another quarter of a million clicks!

Data from 12306 shows that for every train ticket sold that day there were more than one thousand visits. In this "cruel" data, we can sense the homesickness of each individual buyer. On January 9, a total of 5.01 million train tickets were sold online, making up 57.5% of the total sales for the day.