Census-based mobility graph data across 12 U.S. metro regions

This dataset contains mobility information among census tracts for 12 U.S. cities in 2021. Mobility is defined to be the daily commute flow of residents, the data for which is retrieved from the Longitudinal Employer-Household Dynamics (LEHD), a U.S. Census Bureau program. In each of the individual city's directory, the file 'city_network_edges.csv', the 'S000' column the commute flow number between 'origin' and 'destination' census tracts of the city. The geographical boundaries of census tracts are also present in each directory, with 'city_network_nodes' representing shapefiles.本数据集涵盖了2021年美国12座城市的人口普查区域（census tracts）之间的通勤流动性数据。通勤流动性被定义为居民的日常通勤流量，相关数据取自美国人口普查局（U.S. Census Bureau）下属的纵向雇主-家庭动态项目（Longitudinal Employer-Household Dynamics, LEHD）。 在各城市的单独目录中，均包含名为'city_network_edges.csv'的文件，该文件中的'S000'列记录了对应城市的起点(origin)与终点(destination)人口普查区域之间的通勤流量数值。各目录中还附带了该城市人口普查区域的地理边界数据，其中'city_network_nodes'为形状文件（shapefiles）。