TopoJSON viewer
To open a TopoJSON file, drop it in the box below. It opens straight away, even with no extension or the wrong one. Your browser opens it on your device: nothing is uploaded.
What you see
| TopoJSON in the viewer | |
|---|---|
| Sketch | Drawn on your device, fitted to the file, with a scale |
| Map | OpenFreeMap’s map under the features, only after Show map |
| Table | A row per feature with its type, points, length and properties |
| Decoded | Arcs joined into lines and areas, quantized coordinates turned back with the transform |
| Objects | Each object’s name becomes the features’ folder |
| Extensions | .topojson, .json |
| Upload | None: opened on your device |
What is a TopoJSON file?
TopoJSON is a compact form of GeoJSON: shapes that share a border store it once, as arcs, often with whole-number coordinates. D3 maps use it.
Its objects decoded into features, sketched, with a table of their properties and the map on request. Text shows the JSON.
How to open a TopoJSON file
- Add your TopoJSON. Drop the file in the box, choose it or paste it.
- Look at it. Its objects decoded into features, sketched, with a table of their properties and the map on request. Text shows the JSON.
- Take it further. Open in hands it, in a new tab, to File converter.
Questions
Drop it here: every object is decoded and drawn. The converter makes GeoJSON of it.
No. The file is read and sketched on your device. Only Show map asks OpenFreeMap for the map tiles of the area you look at; the file itself is never sent.
No. The viewer runs in your browser and opens the file on your device. Nothing is sent anywhere.