US Census Urbanized Areas (2010)

selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation. After each decennial census, the Census Bureau delineates urban areas that represent densely developed territory, encompassing residential, commercial, and other nonresidential urban land uses. In general, this territory consists of areas of high population density and urban land use resulting in a representation of the "urban footprint." There are two types of urban areas: urbanized areas (UAs) that contain 50,000 or more people and urban clusters (UCs) that contain at least 2,500 people, but fewer than 50,000 people (except in the U.S. Virgin Islands and Guam which each contain urban clusters with populations greater than 50,000). Each urban area is identified by a 5-character numeric census code that may contain leading zeroes. Access Constraints: None, Use Constraints:The TIGER/Line Shapefile products are not copyrighted however TIGER/Line and Census TIGER are registered trademarks of the U.S. Census Bureau. These products are free to use in a product or publication, however acknowledgement must be given to the U.S. Census Bureau as the source. The boundary information in the TIGER/Line Shapefiles are for statistical data collection and tabulation purposes only; their depiction and designation for statistical purposes does not constitute a determination of jurisdictional authority or rights of ownership or entitlement and they are not legal land descriptions.Coordinates in the TIGER/Line shapefiles have six implied decimal places, but the positional accuracy of these coordinates is not as great as the six decimal places suggest. https://www.census.gov/programs-surveys/geography/guidance/geo-areas/urban-rural/2010-urban-rural.html

本数据集选自美国人口普查局主地址文件/拓扑集成地理编码与参考（Master Address File / Topologically Integrated Geographic Encoding and Referencing，MAF/TIGER）数据库（MTDB）中的地理与制图信息。该MTDB为无缝衔接的全国性数据集，各部分之间无重叠与空白；但每份TIGER/Line形状文件（shapefile）均可作为独立数据集单独使用，也可组合使用以覆盖全美范围。
每十年一次人口普查后，美国人口普查局都会划定城市区域：该区域代表高密度开发的地域，涵盖住宅、商业及其他非住宅城市土地利用类型。总体而言，此类地域由高人口密度区域与城市土地利用区域共同构成，呈现为"城市足迹"的形态。城市区域分为两类：城市化地区（urbanized areas，UAs），人口规模达5万人及以上；城市密集区（urban clusters，UCs），人口规模介于2500人（含）至5万人（不含）之间，但美属维尔京群岛与关岛除外——这两地的城市密集区人口规模均超过5万人。每个城市区域均由5位数字的普查编码标识，编码可包含前导零。
访问限制：无。
使用限制：TIGER/Line形状文件产品不受版权保护，但TIGER/Line与Census TIGER为美国人口普查局的注册商标。此类产品可免费用于产品或出版物中，但需注明美国人口普查局为数据源。TIGER/Line形状文件中的边界信息仅用于统计数据采集与制表；其为统计目的所做的表述与指定，并不构成对司法管辖权、所有权或权益的认定，亦不属于合法的土地权属说明。TIGER/Line形状文件中的坐标隐含六位小数，但此类坐标的定位精度并未达到六位小数所体现的水平。
https://www.census.gov/programs-surveys/geography/guidance/geo-areas/urban-rural/2010-urban-rural.html