us-atlas
Pre-built TopoJSON files of U.S. cartographic boundaries from the Census Bureau for mapping.
What is us-atlas?
U.S. Atlas TopoJSON is a collection of pre-built TopoJSON files containing U.S. geographic boundaries from the Census Bureau. It provides ready-to-use nation, state, and county geometries that have been converted, optimized, and projected for mapping applications. This solves the problem of having to download, convert, and process raw Census shapefiles manually.
Data visualization developers, cartographers, and researchers who need U.S. geographic boundaries for web-based mapping projects using libraries like D3.js.
Developers choose this project because it provides clean, consistent, and optimized TopoJSON files that work seamlessly with D3-geo, saving hours of data processing time. The pre-projected versions are particularly valuable as they come ready for display with proper Albers USA projection.
Overview
Pre-built TopoJSON from the U.S. Census Bureau.
Use Cases
Best For
- Creating choropleth maps of U.S. states or counties
- Building interactive data visualizations with D3.js that require U.S. geographic boundaries
- Rapid prototyping of U.S. map visualizations without geographic data processing
- Educational projects teaching geographic data visualization
- Data journalism projects requiring accurate U.S. boundary files
- Dashboard applications displaying data by U.S. geographic regions
Not Ideal For
- Projects requiring international or non-U.S. geographic boundaries
- Applications needing the most up-to-date Census Bureau boundary data (beyond 2017)
- High-precision cartography where simplified geometries compromise accuracy
- Teams using mapping libraries other than D3.js that require different data formats
Pros & Cons
Pros
Provides pre-converted nation, state, and county boundaries from Census shapefiles, eliminating manual data processing steps and saving developers hours of work.
Includes files pre-projected with d3.geoAlbersUsa to fit a standard 975×610 viewport, making them immediately usable in D3-based visualizations without additional setup.
Boundaries are computed by merging lower-level geometries (e.g., states from counties), ensuring no gaps or overlaps and reliable topological consistency across all geographic levels.
Geometries are quantized and simplified to reduce file size while maintaining visual accuracy, making them efficient for web loading and performance in data visualizations.
Cons
Relies on the 2017 Census Bureau cartographic boundaries, so it lacks recent updates or changes, which may be critical for projects requiring current geographic data.
Exclusively covers United States boundaries, making it useless for international mapping projects or those involving other countries' geographic data.
The pre-projected files use a specific Albers USA projection; if a custom projection or different viewport is needed, users must reproject the unprojected files manually, adding complexity.
Frequently Asked Questions
Related Projects
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historical-basemapsCollection of georeferenced boundaries of world countries and cultural regions for use in mapping historical data on global or continental scale
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