Add your GEOJSON file
Drop one or more .geojson files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
GEOJSON to TOPOJSON
Converting a .geojson font to .topojson repackages the same glyphs and metrics for a different delivery target. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop GEOJSON files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting GeoJSON to TopoJSON topology
Converting a .geojson font to .topojson repackages the same glyphs and metrics for a different delivery target. A .geojson file encodes geographic features as JSON: geometries such as Point, LineString and Polygon, each optionally carrying a free-form properties object, usually collected in a FeatureCollection. It is the format web mapping actually runs on.
A .topojson file is a topological encoding of geographic data: shared boundaries are stored once as arcs and referenced by the shapes that use them, with coordinates quantised and delta-encoded. It typically produces files a small fraction the size of the equivalent GeoJSON. For this route the practical draw is dramatically smaller than GeoJSON for data with shared boundaries and shared borders stay identical between neighbours by construction — balanced against not directly consumable — most tools require conversion to GeoJSON first, which is worth knowing before you commit a large batch.
Why convert GEOJSON to TOPOJSON?
The practical trigger for this conversion is usually a mismatch: with .geojson, verbose and large for dense geometry, with no built-in compression. Switching to .topojson buys you dramatically smaller than GeoJSON for data with shared boundaries, which is why it is the better fit for serving choropleth and boundary maps to a browser with minimal payload. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
GEOJSON vs TOPOJSON at a glance
| Aspect | GeoJSON (.geojson) | TopoJSON topology (.topojson) |
|---|---|---|
| Format type | Text-based — characters and structure, so there is no visual quality loss | Text-based — characters and structure, so there is no visual quality loss |
| How it stores data | coordinate order is longitude, latitude — the reverse of how people say it, and the single most common source of bugs | shared boundaries are stored once in a top-level arcs array; geometries reference arcs by index |
| Strongest at | rendering geographic data in Leaflet, Mapbox or OpenLayers | serving choropleth and boundary maps to a browser with minimal payload |
| Weak spot | verbose and large for dense geometry, with no built-in compression | not directly consumable — most tools require conversion to GeoJSON first |
| Metadata | geometry and the properties object are preserved. Styling is not part of the format, so a conversion from KML loses that presentation information rather than GeoJSON dropping it | geometry and per-object properties are preserved. Quantisation means coordinates are reconstructed to the precision the file's transform declares, not to the original source precision |
Pick TOPOJSON as the output
Select .topojson in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if TOPOJSON is selectable, the route is real and validated.
Convert on your device
Press Convert. The font tables are parsed and rewritten locally with fonteditor-core; glyph outlines, hinting, and kerning survive the trip.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid TOPOJSON file. Outputs keep the original filename with the .topojson extension.
GEOJSON to TOPOJSON questions, answered
Will converting GEOJSON to TOPOJSON lose quality?
There is no visual quality to lose — geojson is text-oriented and topojson is text-oriented, so the question is structural fidelity. Text, ordering, and basic structure are preserved; complex layout, embedded objects, and styling beyond the target's model are simplified.
Is it private to convert GEOJSON files here?
Yes — the .geojson file is processed inside your browser tab and never uploaded. The font tables are parsed and rewritten locally with fonteditor-core; glyph outlines, hinting, and kerning survive the trip. Close the tab and the file is gone from memory.
Where will the TOPOJSON file work?
Native to D3 and the TopoJSON client library; QGIS and GDAL can read it, and most other tools want GeoJSON. Novus Convert decodes the transform and arc deltas locally and converts to GeoJSON.
Will the TOPOJSON file be bigger or smaller than my GEOJSON?
It depends on the content: shared boundaries are stored once in a top-level arcs array; geometries reference arcs by index. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my GEOJSON file?
In .geojson, geometry and the properties object are preserved. Styling is not part of the format, so a conversion from KML loses that presentation information rather than GeoJSON dropping it. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.
Can I convert TOPOJSON back to GEOJSON?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .geojson → .topojson → .geojson is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.