Geographic transformation of China's internal population migration from 1995 to 2015: Insights from the migration centerline

Internal population migration in China is one of the most dramatic in the world. To understand the geographic dynamics of the Chinese population migration, we present a revised method called the migration centerline based on the definition of the geographic mean center of the population. Using data from the population censuses and one-percent sample surveys from 1995 to 2015, this study aims to reveal the spatial dynamics and contributors to population movements in China. The main results are as follows. (1) The directions of the population migration centerlines consistently point southeast, while the in- and out-migration centers for the five-year and non-hukou population migrations move north, especially from 2000 to 2010. After 2010, the west-oriented movements of the in-migration centers become pronounced, and migration distances generally decline. Five-year population migration towards the north increases from 2010 to 2015, whereas the non-hukou populations increased in the south in 2015. (2) The main contributors to in-migration centers are the coastal provinces, whereas out-migration centers are mostly inland provinces. (3) The geographic transformation of population migration centerlines is connected to changes in China's economic and population centers, moving south, leading to stable southeast-oriented migrations. In addition, the locations of migration centerlines are consistently further south compared with those of population centers. The migration centerline provides an intuitive and straightforward means for examining the geographic transformation of China's internal population migration and can be applied to various types of human mobilities based on different definitions or multiple spatial scales.