1. Census Geographic Area Programs and Geographic Products Update
Michael Ratcliffe
Geography Division
US Census Bureau
Let’s Focus on Census Geography Workshop
GIS-T
April 11, 2010

2. Public Use Microdata Areas
Minimum population: 100,000
Super-PUMAs will not be defined.
Anticipate publication of proposed criteria in Federal Register, Summer 2010.
Delineation program expected start: Spring 2011.
SDCs will delineate PUMAs.

3. Public Use Microdata Areas
PUMAs will be used to tabulate and present data for:
2010 Census Public Use Microdata Sample (PUMS) Files
American Community Survey PUMS Files
American Community Survey 1-year data

4. PUMAs follow county boundaries where possible
PUMAs follow county boundaries where possible. May cover large land areas due to minimum population requirement.

5. Counties with populations greater than 200,000 may contain multiple PUMAs. Census tracts may be aggregated to form PUMAs.

6. Traffic Analysis Zones
Two types of areas:
Traffic Analysis Zones
Defined based on 2010 census blocks
Traffic Analysis Districts
Aggregations of TAZs

7. Traffic Analysis Zones Draft Program Schedule
Task
Start
Finish
AASHTO/FHWA submits short version of requirements to Census Bureau
November 2009
AASHTO/FHWA submits formal version of requirements to Census Bureau
February 2010
MAF/TIGER Partnership Software Development
February 2011
Spatial Files, MTPS, Delineation Guidelines and Documentation Distributed to MPOs
April 2011
State DOTs and MPOs delineateTAZs and TADs
August 2011
Census Bureau reviews and inserts TAZs into MAF/TIGER database
November 2011

8. Traffic Analysis Zones
TAZ Delineation Software:
MAF/TIGER Partnership Software will be utilized
Block Equivalency Files
Caliper Corporation has reviewed and commented on software requirements
Census Bureau will need a list of counties (towns in New England) associated with each MPO

9. Statistical Areas Program
Census tracts
Block groups
Census county divisions
Census designated places
Delineated areas were entered into the MAF/TIGER data base December 2009
Currently verifying final boundaries

10. Statistical Areas No longer just for the decennial census!
ACS will tabulate data for all statistical areas
Economic Census data tabulated for CDPs:
5,000 or more people
5,000 or more workers

11. Census Tracts and Block Group Thresholds
Census Tract Thresholds
Census 2000
2010 Census
 Population
Population
Housing Unit
Optimum
4,000
1,600
Minimum
1,500
1,200
480
Maximum
8,000
3,200
Block Group Thresholds
Census 2000
2010 Census
 Population
Population
Housing Unit
Optimum
1,500
---
Minimum
600
480
Maximum
3,000
1,200
2.5 persons per Household.
We have had a number of comments asking us to switch to HU counts, because of ease of validation, although data disclosure issues primarily involve population and not HUs. Thus we will allow locals to use either threshold.
In addition, the HU counts allow a better definition of seasonal communities that may receive ACS data.

12. TIGER/Line and Map Products
Public TIGER/Line Shapefiles
Reference Maps
Congressional District maps
P.L County Block Maps
Census Tract Outline Maps
Census 2010 Block Maps
Thematic Maps
Loss and Gain of Seats in Congress by State
Population Distribution (“Nighttime”) Map

13. Geographic Relationship Files
2000 Tabulation Block to 2010 Collection Block
2000 Tabulation Block to 2010 Tabulation Block
2010 Current (ACS) Block to 2010 Tabulation Block
2010 Collection Block to 2010 Tabulation Block
2000 Census Tract to 2010 Census Tract
Other Potential Relationship Files?

14. Geographic Reference Products
Gazetteer Files
Counties
County subdivisions
Places
Geographic Area Inventory Lists (with population, housing units, and land area)
Geographic Change Notes
Geographic Terms and Concepts

15. Questions? Comments?
Michael Ratcliffe Geography Division U.S. Census Bureau