Tag Archives: Block Groups

Analyzing Block Group Demographics

.. tools & data to analyze sub-census tract households, education, income, housing, more … Block Groups, subdivisions of census tracts, are the smallest geographic areas for which “richer demographics” are developed by the Census Bureau. Block group demographic-economic estimates, based on Census 2010 geography, are annually updated beginning with American Community Survey (ACS) 2010. The latest ACS estimates for these 217,740 areas covering U.S. wall-to-wall are from ACS 2015. The ACS 2016 update will be released in December 2017.  See the related Web section for more detail about accessing and using block group geography and demographic-economic data.

Patterns of Economic Prosperity by Block Group
The following graphic shows patterns of median household income by block group in the Houston, TX area. Markers show block groups with 10 or more housing units having value of $2 million or more. Markers are labeled with the number of housing units having value of $2 million or more in that block group. Click graphic for larger view, more detail and legend color/data intervals. This map illustrates the geographic level of detail available using block group demographics and the relative ease to gain insights using geospatial data analytics tools.

– View developed using CV XE GIS and related GIS project.

Block Group Demographic-Economic Data & Shapefiles
… selection of key demographic-economic attributes; annual update
… subject matter categories include:
  • Total population>
  • Population by gender iterated by age
  • Population by race/origin
  • Households by type of household
  • Educational attainment by detailed category
  • Household Income by detailed category
  • Housing units by owner/renter occupancy
  • Housing units by units in structure
  • Housing units by detailed value intervals

See the related Web section for a detailed list of items.

Use these Data on Your Computer
Use the above U.S. national scope dataset with your own software or in ready-to-use GIS projects with the CV XE GIS software.

Join me in a Data Analytics Lab session to discuss more details about accessing and using wide-ranging demographic-economic data and data analytics. Learn more about using these data for areas and applications of interest.

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.

Relating Block Groups to ZIP Code Areas

.. the popularity of block group demographic data is mainly due to this being the smallest geographic area for which annually updated demographic data, with U.S. wall-to-wall coverage, are available from the American Community Survey (ACS) — or any other source. While block groups nest within census tracts from both a geometric and geocode hierarchy perspective, the relationship between block groups and ZIP code areas is far less clear. Analysts are often interested in relating block group geography and demographics with ZIP code areas. The Census 2010 217,740 block groups intersect with 32,824 ZIP code areas forming 308,805 BG-ZIP area combinations. This section reviews tools to examine the relationship between block group geography/demographics and ZIP code areas. See related Web section for full details.

Block Group 06-075-015700-1 in Context of ZIP Code Area 94115
Block groups (BGs) are often wholly contained within a ZIP code area. But around the ZIP code area boundary, intersecting block groups are often split by the ZIP code boundary. This relationship is illustrated in the graphic shown below. This graphic shows block group 06-075-015700-1 (yellow BG code label, cross-hatched, black boundary) in context of ZIP Code area 94115 (white labels, bold blue boundary) located in San Francisco. This GIS application is closely related to the Mapping Block Group Data, also uses the San Francisco area in applications.

– view developed with ProximityOne CV XE GIS and related GIS project.
– view all San Francisco ZIP code areas; see ZIP 94115 in context.

The cross-hatched BG 060750157001 (or 06-075-015700-1) is split by ZIP code 94115. What part of the BG is in ZIP code area 94115 and adjacent ZIP code area 94118? The situation is similar for BG 060750157002, directly below 060750157001, which is split into 3 ZIP code areas. Use the interactive table to make these determinations.

Using the Interactive Table
The interactive table illustrated in the graphic below contains a row for block group area part which intersects with a unique ZIP code area. The simple case of a BG being split into two ZIP code areas can be visually observed as shown in the graphic presented above. A tabular relational table offers processing advantages compared to visual geospatial depictions. Here is an example. ZIP code area 94115 contains whole or parts of 32 BGs. To view/verify this using the table below, 1) click the ShowAll button below the table, then 2) click the Find ZIP button (edit box at right preloaded with this ZIP). The table refreshes with 32 rows — the BGs intersecting with this ZIP code area. Verify there are 32 BGs; the BG codes can be viewed in column 1.

In the above map at the top of this section, block group 06-075-015700-1 is shown visually to be contained in two ZIP code areas. To view how block group 06-075-015700-1 is split among multiple ZIP code areas using the table below, 1) click the ShowAll button below the table, then 2) click the Find GEOID button (enter G0607501057001 in the edit box to right of Find GEOID then click Find button). The table refreshes with two BGs. In this example, it can be seen that the total BG population (Census 2010) is 1,375. The part of the BG population is shown and the percent of the population from that BG allocated to the corresponding ZIP code are shown. This BG has a total area 0.09 square miles. The part of the BG area Census 2010, square miles) is shown and the percent of the area from that BG allocated to the corresponding ZIP code are shown.

Use the main Web section interactive table to examine areas of interest. Join me in a Data Analytics Lab session to discuss use of these data using analytical tools and methods applied to your situation.

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.

MapCompiler: Assembling a GIS Project

.. visual analysis of geographic-demographic-economic patterns is an important part of the data analytics process.  The ability to easily combine and flexibly explore relationships among geographies is equally important.  Use GIS tools to perform these tasks and benefit from collaborative planning and analysis results.

This section summarizes use of “mapcompiler” operations to develop reference or analytic map views for small area geography like that shown in the following graphic.  The graphic shows block groups (red boundaries, yellow labels)  and census tracts (blue boundaries, white labels)

Study Area with Block Groups and Census Tracts Layers
This “application” has been developed to examine characteristics in the vicinity of the red marker (1 Infinite Loop, Cupertino, CA). This location and vicinity are used for illustration. It is easy to see what block group and census tract contain the location of interest. Other locations could be added.

— view developed using CV XE GIS software.

The methods described here can be applied to any location in the U.S. While these steps illustrate use of small area geography, the resources and methods apply to geography and shapefiles on a global level. They include geography ranging from all U.S. counties to the world by country.

Assemble the GIS Project
A first step to view a map of small area geography is to acquire and assemble layers/shapefiles into a GIS project.  Visually compare the geographic relationship between block groups or census tracts by using the CV XE GIS GeoGateway feature. The GeoGateway feature can be thought of as a “mapcompiler” — selectively add shapefiles as layers to a GIS project.  These operations are summarized here and presented step-by-step in this related Web section. The GeoGateway feature is available in all versions of the CV XE GIS software.

Cupertino, CA Study Area
The graphic below shows the start-up view of the GIS project used in this application.

— view developed using CV XE GIS software.

The red marker shows the location of 1 Infinite Circle, Cupertino, CA. Census blocks with blue fill pattern are within 1-mile distance from the address/location. Census blocks with green fill pattern are within 3-mile distance from the address/location. Block groups, census tracts and roads will be added to this GIS project through steps described in this section. The resulting views are shown here.

Use these resources and procedures to develop similarly constructed maps for anywhere in the U.S. While the applications shown here illustrate use of map compiler, or GIS project development tool, for block groups and census tracts, the CV XE GeoGateway can be used to select and combine any of the TIGER/Line shapefiles.

GIS Project Start-up & Development
The following steps are required to operationally proceed with mapcompiler steps:
Install the CV XE GIS software (level 1 or higher) if not already installed.
• Unzip the CAPS1 GIS project fileset to the folder c:\cv_caps (new folder).
• Start CV XE GIS; use File>Dialog>Open to open the GIS project c:\cv_caps\caps_06085_zoom1.gis.
.. the view will be similar to the view shown above.

Summary of Steps to Add Layers
1. Start File>GeoGateway; a new form appears.
2. Add the Santa Clara CA census tracts shapefile/layer.
3. Add the Santa Clara CA block groups shapefile/layer.
4. Add the Santa Clara CA edges/roads shapefile/layer.
5. Close GeoGateway form; perform mapping and analytical operations.

Using GeoGateway
This graphic shows the GeoGateway form being used to integrate the Santa Clara County block groups layer into the GIS project.

See the detailed step-by-step operations.

U.S. Urban Areas
Use the GeoGateway feature to develop national scope map views and GIS projects like the one shown below — all urban areas (orange fill pattern). This view can be assembled in a few minutes, starting with the same GIS project used above.

— view developed using CV XE GIS software.

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.

Interactive Location-Based Demographics Tool

.. have you wondered how Web sites determine the demographic-economic attributes for a location/address? Are those data for the corresponding block group, census tract, city or something else? Was it the “ZIP code area”? These areas can be 100,000 population or more making them so large that alternative geographies might be preferred. Often those important particulars — which geography and data sourcing — are vague or unknown. This section reviews use of the interactive Location-Based Demographics Tool to access data for a location based multiple, alternative types of address “container areas”. See more details in this related web section.

Any given address or location is contained with several types of statistical areas (e.g. census tract or block group) and political areas (e.g. city or county). We may want to know the demographic-economic characteristics of a location for any one or several of these geographies. Use the interactive tool on this page to access those data. For example, access/view the median household income of the location/address block group or the median household income the location/address city. Key in the address of interest, select the type of geography and click Find — see graphic below. The results are displayed on the same page.

Click this graphic to view address entry form

Profile for Census Tract
When Tract is selected as Type of Area, this profile is displayed:
(median household income is $118,827)

Profile for Block Group
When Block Group is selected as Type of Area, this profile is displayed:
(median household income is $139,342)

Creating Maps for These Geographies
See this related web section about using the MapCompiler to create map views for these block group and census tract areas in the vicinity of the default address used above (1 Infinite Loop, Cupertino, CA). Use the CV XE MapCompiler (GeoGateway feature) to create similar maps for any area of interest.

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.

Mapping Block Group Data

.. demographic-economic patterns and characteristics can often be “masked” when using larger geographic areas such as counties and metros. Using data for small area geography such as census tracts and block groups can help identify clusters and areas of interest. Now, demographic-economic data for block groups (217,000 areas averaging 1,200 population covering the U.S. wall-to-wall) are tabulated annually from the American Community Survey (ACS). There are hundreds of subject matter items updated annually. Without specialized tools, it is very difficult to navigate through the maze of small area data that are available and make effective use of these data for analysis and decision-making.

Use the combination of API tools and GIS tools described in this Web section to visually and geospatially analyze demographic-economic characteristics of block groups. Covering the U.S. wall-to-wall and averaging 1,200 population, block groups are the smallest geographic tabulation area for data from the American Community Survey (ACS 5-year estimates). Block group (BG) data are also available from Census 2010 Summary File 1 (SF1) for the same block group area geography.

Patterns of Median Household Income
— San Francisco, CA by Block Group

Create map views similar to the one shown here for your areas of interest.

… Click graphic for larger view. View developed using CV XE GIS.

Install Tools
There are two software tools involved to create maps such as the one above for any county in the U.S. using block group level data for multiple years, flexibly choosing among more than a thousand subject matter items. Steps to use two tools are described in this Web section. You can perform these operations for any area in the U.S. and use the resulting maps and data in any manner.
• Demographic-Economic Data Extraction (DEDE) API tool
CV XE GIS software
See the corresponding Web sections above to install the Windows-based software. There is no fee to use these tools to perform operations described here. There are no block group subject matter datasets to download. The steps to use these tools are summarized here.

Get Help Using these Resources
The flexibility and breadth of data selection options afforded by access to thousands of subject matter items from multiple statistical programs requires several steps to use the data in GIS applications. Join us in a Data Analytics Lab session for additional assistance. We can go through/discuss any aspect of steps summarized here. There is no fee for the Data Analytics sessions.

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.