Baidu Migration Big Data

Baidu Migration Big Data provides indices of migration scale (including an in-migration scale index and an out-migration scale index) recorded in days for 369 cities(4 municipalities directly under the central government, 2 special administrative regions, 293 prefecture-level cities, 7 prefectures, 30 autonomous prefectures, 3 leagues, 29 county-level administrative units directly managed by the province, and Taiwan Province) in China and the percentage of in-migration from a particular city to the total in-migration from that city for each city's in-migration sources. The migration scale index reflects the size of a city's in-migration or out-migration populations and allows for cross-city comparisons. PM_ij is the index of spatial connection of population migration between city i and city j.