Census 2020: Block Groups for San Francisco

<strong>A. SUMMARY</strong>
Census Block groups are the next level above census blocks in the geographic hierarchy. Block groups are a combination of census blocks that is a subdivision of a census tract.A block group consists of all census blocks whose numbers begin with the same digit in a given census tract; for example, block group 3 includes all census blocks numbered in the 300s. More information on the census tracts can be found <u><a href="https://www.census.gov/programs-surveys/geography/about/glossary.html#:~:text=Block%20Groups%20(BGs)%20are%20statistical,data%20and%20control%20block%20numbering.">here</a></u>.

<strong>B. HOW THE DATASET IS CREATED</strong>
The boundaries are uploaded from TIGER/Line shapefiles provided by the <u><a href="https://www.census.gov/cgi-bin/geo/shapefiles/index.php?year=2021&layergroup=Block+Groups">U.S. Census Bureau</a></u>.

<strong>C. UPDATE PROCESS</strong>
This dataset is static. Changes to the census blocks are tracked in multiple datasets. See here for <u><a href="https://data.sfgov.org/d/wymm-gfht">2000</a></u> census tract boundaries.

<strong>D. HOW TO USE THIS DATASET</strong>
This boundary file can be joined to other census datasets on GEOID. Column descriptions can be found on in the <u><a href="https://www.census.gov/programs-surveys/geography/technical-documentation/complete-technical-documentation/tiger-geo-line.2020.html">technical documentation</a></u> included on the census.gov website

<strong>E. RELATED DATASETS</strong>
<u><a href="https://data.sfgov.org/d/tmph-tgz9">Census 2020: Census Tracts for San Francisco</a></u>
<u><a href="https://data.sfgov.org/d/sevw-6tgi">Analysis Neighborhoods - 2020 census tracts assigned to neighborhoods</a></u>
<u><a href="https://data.sfgov.org/d/p2fw-hsrv">Census 2020: Blocks for San Francisco</a></u>
<u><a href="https://data.sfgov.org/d/e2st-aufe">Census 2020: Blocks for San Francisco Clipped to SF Shoreline</a></u>
<u><a href="https://data.sfgov.org/d/6rf8-dnst">Census 2020: Blocks Groups for San Francisco Clipped to SF Shoreline</a></u>

{'A. 摘要': '在地理层级结构中，人口普查区组位于人口普查区之上。人口普查区组是由若干人口普查区构成的次级区域，是人口普查区的组成部分。人口普查区组由同一人口普查区内编号以相同数字开头的所有人口普查区组成；例如，人口普查区组3包括所有编号以300开头的人口普查区。有关人口普查区的更多信息，请参阅<a href="https://www.census.gov/programs-surveys/geography/about/glossary.html#:~:text=Block%20Groups%20(BGs)%20are%20statistical,data%20and%20control%20block%20numbering.">此处</a>。', 'B. 数据集的创建方式': '该数据集的边界数据来源于美国人口普查局提供的TIGER/Line形状文件。<a href="https://www.census.gov/cgi-bin/geo/shapefiles/index.php?year=2021&layergroup=Block+Groups">美国人口普查局</a>提供了这些形状文件。', 'C. 更新过程': '该数据集为静态数据集。人口普查区的变更情况追踪在多个数据集中。有关2000年人口普查区边界的更多信息，请参阅<a href="https://data.sfgov.org/d/wymm-gfht">此处</a>。', 'D. 如何使用此数据集': '该边界文件可以与其他基于GEOID的人口普查数据集进行连接。列描述可以在人口普查局网站上的<a href="https://www.census.gov/programs-surveys/geography/technical-documentation/complete-technical-documentation/tiger-geo-line.2020.html">技术文档</a>中找到。', 'E. 相关数据集': '相关数据集包括：<a href="https://data.sfgov.org/d/tmph-tgz9">旧金山2020年人口普查区</a>、<a href="https://data.sfgov.org/d/sevw-6tgi">分析邻里区 - 2020年分配给邻里的人口普查区</a>、<a href="https://data.sfgov.org/d/p2fw-hsrv">旧金山2020年人口普查区</a>、<a href="https://data.sfgov.org/d/e2st-aufe">旧金山2020年人口普查区（剪裁至旧金山海岸线）</a>、<a href="https://data.sfgov.org/d/6rf8-dnst">旧金山2020年人口普查区组（剪裁至旧金山海岸线）</a>。'}