Daily Archives: July 11, 2018

Census Block, Block Group & Census Tract GeoDemographics

Census tracts, block groups and blocks are the important small area statistical geographic areas for which data from Census 2010 are tabulated. Data for census tracts and block groups are also tabulated annually from the American Community Survey. For example. in December 2018, we will have new “richer demographics” annual estimates centric to each year 2008 through 2015 for Census 2010 tracts and block groups … data such as educational attainment, language spoken, housing and household characteristics,  income characteristics and employment and other demographic-economic attributes.

Largest Population New York City (NYC) Census Blocks
The following graphic shows the NYC Census 2010 census block having the largest Census 2010 population that is not a group quarters population block. The Lincoln Center census block shown in the graphic (red boundary) has 4,067 population and 2,922 housing units.

– click graphic for larger view; view developed using CV XE GIS

This block (36 061 015500 6000) occupies 0.033 square miles. It has a population density of 122,333 (population per square mile). The NYC block with the largest population is on Rikers Island and has a group quarters population of 8,634 and 0 housing units. For Census 2010, there were 350,169 census blocks covering the state of New York; 13,356 census blocks were water blocks. For the State of New York, as of Census 2010 the average census block population was 55 (57 excluding water blocks).

Census 2010 and Census 2020
These geographies have generally stable geographic areas and codes from one decennial census (e.g., Census 2010) to the next (e.g., Census 2020). Many of these areas will change in terms of code and area for Census 2020, though the geographic changes will typically be small or not at all.

Census 2020 block, block group and tract codes and geometry will be available in late 2020. Initial block level demographics will be available in March 2021.

Census 2010 & Current GeoDemographics
These areas cover the U.S. from wall-to-wall and generally non-changing in terms of boundary and geographic code (geocode) until Census 2020. This section provides a summary of new Web pages with more detail about each of these geographies:
census tracts and tract codes .. 73,056 areas
census block groups and block group codes .. 217,740 areas
census blocks and block codes .. 11,078,297 areas

Each of these pages provides an interactive table to view tallies of Census 2010 for each of these small area geographies.

Combining Address Data with Small Area Geography
The address of the Office of the California Secretary of State, located at 1500 11th St, Sacramento, CA 95814, was geocoded using the APIGeocoder and converted into a shapefile for Geographic Information System applications.  The location is shown as a red marker in the map views shown below, illustrating each type of small area geography: tracts. block groups and blocks.

Census Tracts
Tracts are labeled with green tract codes. Address 1500 11th St, Sacramento, CA 95814 is shown by red marker.  The address is in tract 06067001101.

View created using CV XE GIS.

Block Groups
Block groups are labeled with red block group codes.  Tract 06067001101 is comprised of block groups: 060670011011 and 060670011012.  See pointer in map view; the block group within tract boundary.

View created using CV XE GIS.

Zoom-in to Census Block
Blocks are labeled with yellow block codes. The address is located in block 060670011011085.

View created using CV XE GIS.

Further Zoom-in Showing Streets
Streets are labeled with street names. Identify tool is used to show mini-profile for 1500 block of 11th Street.

View created using CV XE GIS.

Is the tract code 11.01 or 001101?
Both. Census tracts within a county are identified by a 4-digit basic code between 0001 and 9999, and may have a 2-digit suffix ranging from .01 to .98; for example, 6059.02. The decimal point separating the 4-digit basic tract code from the 2-digit suffix is shown in Census Bureau printed reports and maps. For geo-referencing, the decimal point is implied and does not appear; the 6-character tract code with lead zeroes is used — a character string with no blanks and all numbers.

Accessing and Using these Geographies & Related Demographics
There are several ways these geographies can be used.
• The geocodes are the “handles” to access demographic-economic statistical data.
• The geographies may be visually, geospatially, related as shapefiles.
.. the Census Bureau makes these shapefiles available for use in user appications.
.. the shapefiles typically do not include demographic-economic data.

Access Census 2010 Census Block (and Block Group/Tract) data:
• P.L. 94-171 Redistricting Data — http://proximityone.com/cen2010_pl94171.htm
• Summary File 1 — http://proximityone.com/cen2010_sf1.htm

Access Census Block Group and Tract richer demographics:
• 2016 American Community Survey (ACS) 5-year estimates
  — http://proximityone.com/acs1216.htm
• Access annual counterparts to above section
• Census blocks — http://proximityone.com/cenblk.htm
• Census block groups — http://proximityone.com/blockgroups.htm
• Census tracts — http://proximityone.com/tracts.htm

Alternatively use the Census Bureau APIs or CV XE GIS APIGateway.

Data Analytics Web Sessions
.. is my area urban, rural or …
.. how do census blocks relate to congressional district? redistricting?
.. how can I map census block demographics?
Join me in a Data Analytics Web Session, every Tuesday, where we review access to and use of data, tools and methods relating to GeoStatistical Data Analytics Learning. We review current topical issues and data — and how you can access/use tools/data to meet your needs/interests.

About the Author
Warren Glimpse is former senior Census Bureau statistician responsible for innovative data access and use operations. He is also the former associate director of the U.S. Office of Federal Statistical Policy and Standards for data access and use. He has more than 20 years of experience in the private sector developing data resources and tools for integration and analysis of geographic, demographic, economic and business data. Contact Warren. Join Warren on LinkedIn.