GeoJSON → TopoJSON Converter

Convert GeoJSON to TopoJSON to optimize polygon datasets for performance. TopoJSON reduces file size by encoding shared arcs—great for web maps with many polygons sharing borders.

What is TopoJSON?

TopoJSON is a topology-aware extension of GeoJSON that encodes shared arcs to reduce file size, especially for polygon boundaries. When multiple polygons share borders (like countries, states, or counties), TopoJSON stores each shared boundary only once.

Benefits

• Smaller file size: Often 50-80% smaller than equivalent GeoJSON
• Faster downloads: Less data to transfer means faster page loads
• Preserved topology: Shared boundaries are guaranteed to align perfectly
• Web-friendly: Works with D3.js and other visualization libraries

How to Convert

GeoJSON → TopoJSON

1. Drag and drop your GeoJSON file or click to browse
2. Preview the result on the map
3. Download the optimized TopoJSON file

TopoJSON → GeoJSON

1. Upload your TopoJSON file
2. The tool converts it back to standard GeoJSON
3. Download and use with any GeoJSON-compatible tool

Use Cases

• Web maps with many polygons: Country boundaries, state maps, county maps
• Interactive visualizations: Choropleth maps, election maps, census data
• Performance optimization: Reduce bandwidth and improve load times
• Data distribution: Smaller files are easier to share and embed

Technical Details

• Coordinate precision: Configurable when converting to TopoJSON
• Topology encoding: Automatically detects and preserves shared arcs
• Standards compliant: Follows the TopoJSON specification
• Client-side processing: Your data never leaves your browser

FAQs

When should I use TopoJSON instead of GeoJSON? Use TopoJSON for polygon datasets with shared boundaries (countries, administrative regions). For point data or simple features, GeoJSON is usually sufficient.

Can I use TopoJSON with Leaflet or Mapbox? Yes, but you'll need to convert it back to GeoJSON first (or use libraries like topojson-client).

Does TopoJSON support all GeoJSON features? TopoJSON supports geometries and properties. Some GeoJSON extensions may not be preserved.

See Also

• Back to All Converters
• Shapefile → GeoJSON
• GeoJSON Minifier — Further reduce GeoJSON file size
• TopoJSON Minifier — Optimize TopoJSON files