TIGER/Line Shapefiles

TIGER/Line Shapefiles
Name	TIGER/Line Shapefiles
Type	Spatial dataset
Creator	United States Census Bureau
First release	1990
Format	Shapefile, GeoJSON, GDB
License	Public domain (US)

TIGER/Line Shapefiles

TIGER/Line Shapefiles provide digital cartographic data for United States geography, delivering machine-readable representations of roads, boundaries, and address features used for United States Census Bureau operations, Bureau of Land Management mapping, and municipal planning in cities such as New York City, Los Angeles, and Chicago. The dataset underpins spatial analysis for agencies like the Federal Emergency Management Agency, research at institutions such as Massachusetts Institute of Technology and Stanford University, and private-sector services from firms like Esri, Google, and Microsoft.

Overview

The product is a set of spatial files that encode United States Census Bureau-defined geographies including census tracts, census blocks, counties, and states, integrating linear features used by agencies such as the United States Postal Service, Federal Communications Commission, and Department of Transportation. Planners from New York City Department of City Planning and researchers at University of California, Berkeley use the data alongside basemaps from National Oceanic and Atmospheric Administration and United States Geological Survey.

History and Development

Origins trace to efforts by the United States Census Bureau in the 1980s to modernize geographic tabulation, building on cartographic work by the U.S. Geological Survey and influenced by computer mapping projects at Bell Labs and IBM Research. Major updates paralleled technological shifts driven by milestones like the release of ArcGIS by Esri and the adoption of Global Positioning System surveying by agencies including the National Geospatial-Intelligence Agency. Prominent collaborations involved academic centers such as Harvard University's mapping labs and companies like Trimble for field collection.

Data Content and Structure

Files include feature classes representing roads, railroads, hydrography, legal and statistical boundaries, and address ranges; these mirror definitions used by entities such as Internal Revenue Service, Centers for Disease Control and Prevention, and Environmental Protection Agency. Schema aligns with shapefile components (.shp, .shx, .dbf) developed in association with standards from Open Geospatial Consortium members and interoperability work by National Information Standards Organization. Attributes reference identifiers used by Federal Election Commission and regional offices like California Department of Finance.

Formats and Distribution

Originally distributed as plain shapefiles, the dataset is now available in formats usable by QGIS and commercial products from Esri; derivatives appear as GeoJSON and file geodatabases used by organizations including United Nations agencies and multinational corporations like Amazon (company). Annual and mid-decade releases coordinate with decennial operations of the United States Census Bureau and with technology platforms such as GitHub and cloud services provided by Amazon Web Services and Google Cloud Platform.

Uses and Applications

Applications span redistricting work for entities like the National Association of Counties, emergency response mapping by Federal Emergency Management Agency, urban planning in municipalities including San Francisco, transportation modeling used by Federal Highway Administration, and epidemiological studies at Johns Hopkins University and Centers for Disease Control and Prevention. Commercial developers at companies such as Uber Technologies, Inc., Airbnb, and Waze integrate TIGER-derived layers for routing, geocoding, and spatial analytics serving customers across sectors including finance firms like Goldman Sachs and retailers like Walmart.

Limitations and Accuracy

Positional accuracy reflects source compilation methods and varies between metropolitan centers like Houston and rural counties across states such as Alaska and Montana; users in research groups at University of Michigan and agencies like the National Transportation Safety Board must account for edge-matching issues and temporality when comparing to datasets from USGS topographic surveys or commercial imagery providers such as Planet Labs and Maxar Technologies. Boundary definitions follow legal frameworks applied by courts like the Supreme Court of the United States and statutes from Congress of the United States but may lag administrative changes tracked by state offices like New York State Department of State.

Access and Licensing

Distributed by the United States Census Bureau and in the public domain like other federal works, the files are usable by municipalities including Los Angeles County and federal programs such as National Flood Insurance Program without restriction; downstream services from companies like Mapbox and non-profits such as OpenStreetMap often combine TIGER-derived data with proprietary layers, observing attributions and community guidelines where applicable.

Category:Geographic information systems