“百度迁徙”下中国城市间的人口流动空间格局
The Spatial Pattern of Population Flow among Cities based on “Baidu Migration”

利用“百度迁徙”数据中2015年第1季度的369个城市之间逐日的人口迁徙数据，分析我国城市间的人口流动空间格局． 研究发现，城市之间的人口流动呈明显的分层集聚格局，形成了长三角、珠三角、京津唐、成渝四大和乌鲁木齐（昌吉）、西宁（海东）、榆林（鄂尔多斯）、昭通四小网络体系，而海西、东北、华中和西南等地区并未出现高层级集散城市和网络体系，这与其区域在国家区域发展战略中的地位在一定程度不匹配． “胡焕庸线”很好地反映了人口流动格局差异，东南壁内部各城市间的人口集散量是西北壁的12.80倍． 跨城市间的人口流动海量数据也应证了城市间的人口联系强度符合重力模型检验．
： The spatial patterns for population flow among 369 cities in China based on “Baidu Migration” dataset collected during the period from February 7 to May 16 in 2015 are analyzed in this paper. The research results show that Chinese urban network based on population flow among cities has a clear hierarchical structure and level distinction which contains four main urban network systems,i.e. Yangtze River Delta, Pearl River Delta, Beijing Tianjin Tang and Cheng Du Chongqing, and four sub urban network systems,i.e. Urumqi (Changji), Xining (Hai-dong), Yulin (Ordos) and Zhaotong (Yibin). But Haixi area, Northeast China, Central China and Southwest China do not appear obvious urban network systems and those conditions do not match the status in national regional development strategy of those areas. “Hu Huanyong” line can reflect the spatial patterns of population flow at among cities, reflecting the profound influence of geographical environment on the population daily flow among cities. The scale of population flow among cities in southeast side of “Hu Huanyong” line is 12.80 times of that of northwest side with “Hu Huanyong line”. The Gravity model can test the population flow among cities based on mass inter-cities population flow data