MAF/TIGER Accuracy Improvement Program

(MTAIP)

Indiana GIS 2005 ConferenceMarch 10, 2005

Indianapolis, Indiana

What is TIGER? Topologically Integrated Geographic Encoding and Referencing

TIGER Content

• Street centerlines and their names

• Lakes, streams, and their names

• Railroads

• Geographic entity boundaries, names, and

codes (for governmental units, census

tracts, census blocks, etc.)

• Housing unit locations

• Key geographic locations (for airports, schools, etc.)

• ZIP Codes and address ranges (for streets with city-style addresses)

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A street center-line “digital map” (geographic data base) of the entire United States, Puerto Rico, and the associated Island Areas

What is the MAF? Master Address File

The content of the MAF is

• Mailing address, if one exists

• Descriptive address, if no mailing

address is known

• Census geographic location

• Source and history data

All addresses and locations

MUST be kept confidential

An accurate and up-to-date inventory of all known living quarters in the United States, Puerto Rico, and Associated Island areas

Why Realign TIGER?

• Support use of GPS by Census Field Staff

- Ongoing Surveys (ACS, CPS, etc.)

- 2010 Census

• Improve Accuracy of Housing Unit Assignment to Correct Census Block

- Goal: 99.6% geocoding accuracy of a housing unit

to correct census block

Major MAF/TIGER IssuesLocation Information of Mixed/Variable Accuracy

Large non-uniform differences in location accuracy exist in a relatively small area, and no detailed quality measures document the extent of street and address errors

Mason

Starbridge

Major MAF/TIGER Issues

Inaccurate MAF/TIGER locations constrain efforts to exchange highly accurate location information with willing geographic partners that have GIS files – and preclude adoption as the road and boundary layers in The National Map

In addition, the “home grown” MAF/TIGER processing environment makes development of Web-based review and update processes more cumbersome

Roads in TIGER/housing units in MAF not in “true” geographic locations

TIGERGIS

Major MAF/TIGER Issues

Good GPS structure locations over mislocated MAF/TIGER street centerlines would put many houses on the wrong side of the street and, therefore, in the wrong census block

Inaccurate locations preclude adopting GPS locational technology for the American Community Survey and the 2010 Census until MAF/TIGER has locations corrected

Major MAF/TIGER Issues

Stream mistakenly crosses several streets to form “census blocks” that do not exist

The problem is how to show the true situation correctly in the future, while maintaining an historical link to Census 2000 block numbers

Kirkwall

Alcorn Bayuo

“Truth” Contradicts Existing Feature Topology

COverup

MTAIP Implementation

Decision was made to enlist the assistance of a contractor or a consortium of contractors to undertake MTAIP

Census Bureau

Harris Corporation

Improves the Spatial Data base – is not directed to improve coverage issues

MTAIP IMPLEMENTATION

Primary Strategy: Use State/Local/Tribal GIS Files (7.6 Meter Min. Spatial Accuracy Standard)

Preference is to work with: states/tribescountieslocal governments

Secondary Strategy: Where we cannot obtain a file from a gov’t, our Contractor will obtain a source for realignment (HAS): - Uses vector files as input to the realignment process

• Will not deal with governments• Checks for available private sector GIS files• Subcontracts for vectors extracted from imagery (existing or new)• Subcontracts for street centerline collect using GPS

Secondary Strategy: Use Highly Accurate Private-Sector GIS Files, Where Available

Tertiary Strategy: Obtain Vectors using the most cost-efficient approach

What Will MAF/TIGER Be After Enhancement?

Accurate MAF structure locations over correctly located TIGER street centerlines allow GPS devices to put field staff and houses on the correct side of the street and, therefore, in the correct census block

Highly Accurate MAF/TIGER locations will foster use of GPS locational technology for the American Community Survey and the 2010 Census

Before

After

What Does the Census Bureau/Federal Government Get?

• Improved address and map accuracy• More effective Geographic Partnerships• Major contribution to a more effective/lower cost 2010

Census, ACS, and other household survey operations

• Source for the National Map (Roads and Boundaries)• Source for Homeland Security, Geospatial One-Stop,

and the NSDI

• Gives the Bureau the ability to more accurately collect and

tabulate data for local governments (Funding $$$ are based on Population Counts)

• Will put the Census Bureau on the same base as the state/local/tribal GIS databases where they exist

• Will enable easier exchange of spatial information between state/local/tribal governments and the Census Bureau

(Features and Boundaries)

What Do the Locals Get?

MTAIP Production Schedule

Initial Realignment | 250 | 600 | 610 | 700 | 690 | 383

Cumulative | 250 | 850 | 1,460 | 2,160 | 2,850 | 3,233

0

100

200

300

400

500

600

700

FY 2003 FY 2004 FY 2005 FY 2006 FY 2007 FY 2008

MTAIP Production Schedule

• Counties are scheduled in early summer each year for the next fiscal year (May/June timeframe)

• Schedule for the remaining counties is revised each summer

• Need to have all state/county/local files in house by April, 2006

• Fiscal Year 2005 county workload is specified in contract

Digital Layers Desired

•Street Centerline File

• Hydrography

• Rail Features

• Boundaries

• Digital Orthos

• Structure Coordinates or Building Footprints

• Cadastral or Tax Parcels

• Land Use Boundaries

• Key Geographic Locations

• Natural Resource Pipelines

• Electric Power Transmission Lines

• ZIP Code Boundaries

• Census Statistical Entity Boundaries

• Emergency Service Zone Boundaries

METADATA METADATA METADATA METADATA

Data Agreements

• Let me know up front about use constraints, data sharing agreements, etc.

• We usually always request revisions to your agreement: takes time (and patience!)

• Handle outside the metadata arena, please

Source File Evaluation

• Files must meet the Bureau’s 7.6 meter spatial accuracy standard• File Evaluation based on 110 GPS points, CE 95• Files meeting the 7.6 meter requirement are considered for

TIGER coordinate enhancement

• If file does not meet 7.6 meter requirement - attributes or other

characteristics may be used

• Addresses, structure coordinates, and boundaries are evaluated

separately

MTAIP Feedback to Source Providers•Report on spatial evaluation of CL file

MTAIP Feedback to Source Providers

• 2004 TIGER/Line files-First Edition - Released January 2005 -includes feature level metadata on

coordinates - Second Edition 6 months later

• State/Local/Tribal source providers will be provided with “Local Edition” TIGER/Line File

- After Public Release TIGER/Line - Will Include additional Record Types (beyond those in the 2004 T/L

File) that will contain feature name and/or address range information as provided to the Census Bureau (except for single address address ranges)

INDIANA MTAIP Status

COUNTY STATUS

7 TIGER Re-aligned TSC&L File

22 TIGER Realigned HAS

16 Local File Acquired

28 Negotiating for Acquisition

13 Local Centerline Future Availability

6 Harris-Acquired Source

NEXT STEPS: Maintenance

• Working on a plan-especially to support ACS post 2010

• First-level maintenance: work with partners who provided street centerlines for the initial realignment

- Preference is a single contact in state whenever possible

- Census Bureau would process any updates in-house,

since we would be on the same spatial database

Why Provide a Street Centerline File?

• Subsequent Census Bureau geographic products should align with street centerlines in the file provided

• Governments will be able to participate in future Census Bureau geographic programs using spatial data transfers: LUCA, redistricting, census tracts, CDPs, Boundary & Annexation Survey (BAS)

• Transfer of 2010 census geography (tracts, blocks) into state/local/tribal GIS should be easier – spatial transfer

Questions?

Gail A. Krmenec

U. S. Census Bureau

Chicago Regional Office

(708) 562-1738

gail.a.krmenec@census.gov