2020 Census Tracts for King County

For more information about this layer please see the GIS Data Catalog. This layer contains a unique geographic identifier (GEO_ID_TRT) for each tract group that is the key field for the data from censuses and surveys such as Decennial Census, Economic Census, American Community Survey, and the Population Estimates Program. Data from many of the Census Bureau’s surveys and censuses, are available at the Census Bureau’s public data dissemination website (https://data.census.gov/). All original TIGER/Line shapefiles and geodatabases with demographic data are available atThe TIGER/Line Shapefiles are extracts of selected geographic and cartographic information from the Census Bureau's Master Address File (MAF)/Topologically Integrated Geographic Encoding and Referencing (TIGER) Database (MTDB). The shapefiles include information for the fifty states, the District of Columbia, Puerto Rico, and the Island areas (American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, and the United States Virgin Islands). The shapefiles include polygon boundaries of geographic areas and features, linear features including roads and hydrography, and point features. These shapefiles do not contain any sensitive data or confidential data protected by Title 13 of the U.S.C.Census tracts are small, relatively permanent statistical subdivisions of a county or equivalent entity, and are reviewed and updated by local participants prior to each decennial census. The primary purpose of census tracts is to provide a stable set of geographic units for the presentation of decennial census data. Census tracts generally have a population size of 1,200 to 8,000 people with an optimum size of 4,000 people. The spatial size of census tracts varies widely depending on the density of settlement. Ideally, census tract boundaries remain stable over time to facilitate statistical comparisons from census to census. However, physical changes in street patterns caused by highway construction, new development, and so forth, may require boundary revisions. In addition, significant changes in population may result in splitting or combining census tracts. Census tract boundaries generally follow visible and identifiable features. Census tract boundaries may follow legal boundaries. State and county boundaries always are census tract boundaries in the standard census geographic hierarchy. Census Tract Codes and Numbers—Census tract numbers have up to a 4-character basic number and may have an optional 2-character suffix, for example, 1457.02. The Census Bureau uses suffixes to help identify census tract changes for comparison purposes. Full documentation: https://www2.census.gov/geo/pdfs/maps-data/data/tiger/tgrshp2020/TGRSHP2020_TechDoc.pdf

如需了解本图层的详细信息，请参阅地理信息系统（GIS）数据目录。本图层为每个普查片区组配备了唯一地理标识符（GEO_ID_TRT），该标识符是人口普查与各类调查数据的关键字段，涵盖十年一次人口普查（Decennial Census）、经济普查（Economic Census）、美国社区调查（American Community Survey）以及人口估计项目（Population Estimates Program）所产生的数据。美国人口普查局（Census Bureau）的多数普查与调查数据均可通过该局公开数据发布网站（https://data.census.gov/）获取。所有带人口统计数据的原始TIGER/Line形状文件（shapefile）与地理数据库均可获取，TIGER/Line形状文件是从美国人口普查局主地址文件（Master Address File, MAF）/拓扑集成地理编码与参照数据库（Topologically Integrated Geographic Encoding and Referencing Database, MTDB）中提取的精选地理与制图信息。此类形状文件覆盖全美50个州、哥伦比亚特区、波多黎各以及各岛屿地区（美属萨摩亚、北马里亚纳群岛联邦、关岛与美属维尔京群岛）。形状文件包含地理区域与要素的多边形边界、道路与水文等线性要素，以及点状要素。此类形状文件不包含受美国法典第13编（Title 13 of the U.S.C.）保护的敏感数据或机密数据。普查区（Census tract）是县或等效行政单元下的小型、相对固定的统计分区，每十年人口普查前会由本地参与方进行审核与更新。普查区的核心用途是提供一套稳定的地理单元，用于展示十年一次人口普查数据。普查区的人口规模通常为1200至8000人，最优规模为4000人。普查区的空间面积因聚居密度差异存在显著波动。理想情况下，普查区边界应长期保持稳定，以便于不同普查周期的统计数据对比。但公路建设、新开发项目等导致的街道格局物理变化，可能需要对普查区边界进行修订。此外，人口规模的显著变化可能导致普查区被拆分或合并。普查区边界通常遵循可见且可识别的地物，也可能与法定边界重合。在标准普查地理层级中，州界与县界始终作为普查区边界。普查区代码与编号——普查区编号最多包含4位基本数字，可附带可选的2位后缀，例如1457.02。美国人口普查局通过后缀来区分普查区的变更，便于数据对比。完整技术文档：https://www2.census.gov/geo/pdfs/maps-data/data/tiger/tgrshp2020/TGRSHP2020_TechDoc.pdf