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Topologically Integrated Geographic Encoding and Referencing (TIGER)

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Topologically Integrated Geographic Encoding and Referencing (TIGER)

Overview

Topologically Integrated Geographic Encoding and Referencing (TIGER) is a digital geographic database developed by the US Census Bureau to support its mapping and geographic programs. Originally created for the 1990 decennial census, TIGER provides a comprehensive, topologically structured representation of geographic features across the United States, including roads, boundaries, water features, and address ranges.

External Resources

Key Concepts

Topology refers to the mathematical relationships between geographic features (adjacency, connectivity, containment) that ensure data integrity. Line features include roads, railroads, rivers, and boundaries represented as connected line segments. Area features are polygons representing geographic areas such as census tracts, counties, states, and water bodies. Point features represent discrete locations such as landmarks or address points. Address ranges are the low/high address numbers associated with street segments for geocoding purposes. FIPS codes are Federal Information Processing Standards codes used to uniquely identify geographic entities. GEOID is a geographic identifier that concatenates FIPS codes to create unique identifiers for census geographies.

Data Products

TIGER/Line Shapefiles

The primary distribution format containing:

  • Legal boundaries: States, counties, cities, townships, congressional districts
  • Statistical boundaries: Census tracts, block groups, blocks, ZCTAs (ZIP Code Tabulation Areas)
  • Physical features: Roads, railroads, water features, landmarks
  • Address data: Address ranges for geocoding applications

Cartographic Boundary Files

Simplified, clipped versions of TIGER/Line files optimized for:

  • Thematic mapping and visualization
  • Smaller file sizes (coastlines clipped to shoreline)
  • Generalized geometries for faster rendering

Geographic Hierarchy

Nation
├── Region
│   └── Division
│       └── State
│           ├── County
│           │   ├── County Subdivision
│           │   ├── Census Tract
│           │   │   └── Block Group
│           │   │       └── Block
│           │   └── Place (City/Town)
│           └── Congressional District
└── Metropolitan/Micropolitan Statistical Area

Applications

  • Geocoding: Converting addresses to coordinates using TIGER address ranges.
  • Redistricting: Analyzing and drawing political boundaries.
  • Demographic analysis: Joining census data to geographic boundaries.
  • Urban planning: Infrastructure and zoning analysis using standardized boundaries.
  • Real estate: Parcel mapping, market area definition, location analysis.
  • Emergency services: 911 addressing and response routing.

Limitations

  • Address ranges are interpolated estimates, not precise address locations.
  • Data updates occur annually; may lag behind real-world changes.
  • Road network geometry may not match other commercial datasets.
  • Designed primarily for census operations, not navigation or routing.

Appendix

Created: 2025-12-01 | Modified: 2025-12-13

See Also

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