Windows
Compatible applications
Quick Facts
Basic information about this file format
Extension
.TOPOJSON
File Type
TopoJSON
Category
Data
Best first step
Use compatible software
Quick Summary
A practical overview of the .topojson file format
TopoJSON is an extension of GeoJSON that encodes topology. Rather than representing geometries as independent sets of coordinates, TopoJSON geometries are stitched together from shared line segments called arcs. Arcs are sequences of points, and geometries are defined as sequences of arcs. This red…
File extension
.TOPOJSON
File type
TopoJSON
Category
Data
Recommended action
Open with a trusted compatible app
How to open a .topojson file
Start with a trusted app that supports this format
- Check the file extension carefully and confirm that the file name really ends with .topojson.
- Use software that supports this file type. If one app does not work, try another compatible program for the same platform.
- Update the application if the file was created by a newer version of the software.
- Scan files from unknown sources before opening them, especially documents, archives, scripts, installers, and executable files.
What is a .topojson file?
File extension details and usage information
TopoJSON is an extension of GeoJSON that encodes topology. Rather than representing geometries as independent sets of coordinates, TopoJSON geometries are stitched together from shared line segments called arcs. Arcs are sequences of points, and geometries are defined as sequences of arcs. This reduces redundancy and file size, making it more efficient for web-based mapping and visualization. TopoJSON files are typically smaller than equivalent GeoJSON files, especially for complex geometries with shared boundaries. This efficiency is crucial for delivering map data quickly over the internet. TopoJSON also allows for topology-aware operations, such as simplification and generalization, which can further reduce file size without sacrificing visual quality. It's widely used in web mapping libraries like D3.js and Leaflet for creating interactive maps and visualizations. The format is particularly well-suited for representing geographic data with shared boundaries, such as administrative regions or river networks.
Software Compatibility
Programs that may open or work with .topojson files
macOS
Compatible applications
Linux
Compatible applications
Mobile
Mobile applications
Can .topojson files be converted?
Options for saving or exporting this file to another format
In many cases, a .topojson file can be converted by opening it in compatible software and using an option such as Save As, Export, or Convert. The available output formats depend on the file type and the application used.
- Use the original software that created the file when possible.
- Check whether the application supports exporting to common formats.
- Be careful with online converters when working with private, business, or sensitive files.
- If conversion fails, the file may be corrupted, incomplete, encrypted, or not actually a .topojson file.
Why can't I open a .topojson file?
Common reasons this file type may not open correctly
Wrong software
The file may require a specific program that supports the .topojson format.
Incorrect extension
The file extension may have been renamed manually, even though the actual file format is different.
Corrupted file
The file may be incomplete, damaged during download, or transferred incorrectly.
Outdated app
Your software may need to be updated before it can open newer versions of this file format.
Frequently Asked Questions
Common questions about .topojson files
To open a .topojson file, use software that supports this file format.
- QGIS
- ArcGIS Pro
- GDAL
- ogr2ogr
- ArcGIS
Open the file in compatible software and look for options such as Save As, Export, or Convert. If no export option is available, the file may require a specialized converter or the original application that created it.
- Verify that the file extension is correct.
- Install or update compatible software.
- Try another application that supports this format.
- Check whether the file is corrupted, incomplete, or encrypted.
A file extension alone does not guarantee whether a file is safe or unsafe. Only open files from trusted sources, scan unknown files before opening them, and be especially careful with executable, script, archive, and document files.
File safety tips
Use caution with unknown files
Only open files from trusted sources. Before opening a .topojson file, scan it with antivirus software, verify that the file extension is expected, and avoid running unknown executable, installer, macro-enabled document, or script files.