View TopoJSON files in your browser
GeoJSON's smaller cousin, made for D3's maps, where neighbors share their borders. Open a TopoJSON right here on a map. The file never leaves your device.
Or drop it anywhere on this page
What you'll see
Your file opens on a map, framed to fit, its layers drawn over OpenStreetMap's streets and what it holds listed beside it.
- OpenStreetMap, dark or light • Flat or a globe
- Every layer and feature in a list • Search their names and fields
- Click a feature for its fields • Measure distances
- Export • PNG, GeoJSON, GPX, KML and CSV
About TopoJSON
Mike Bostock, who made D3, created TopoJSON in 2012 to shrink maps for the web. News sites and data visualizations use it for countries, states and counties, and the world-atlas and us-atlas packages ship it.
Instead of repeating a border for each side, a TopoJSON keeps it once as an arc, and shapes list the arcs they are made of. Coordinates are usually quantized to whole numbers with a transform, which makes the file a fraction of its GeoJSON.
Filepeek puts the arcs back together into shapes in your browser and draws each object as a layer over OpenStreetMap. Click a feature for its properties, and save the features as GeoJSON, KML, GPX or CSV, or the view as PNG.
TopoJSON
.topojson
Format
- MIME type
- application/json
- Made by
- Mike Bostock
- Released
- 2012
Inside the file
- Holds
- Objects made of shared arcs
- Borders
- Kept once for both sides
- Coordinates
- Quantized with a transform
- Built on
- JSON
Opens in every browser
Filepeek opens TopoJSON files on a map in Chrome, Edge, Firefox and Safari. On their own, browsers download them.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Apps that open TopoJSON
- WindowsQGIS reads it • mapshaper converts it
- MacQGIS reads it • mapshaper converts it
- iPhone and iPadNo app opens it
- AndroidNo app opens it
Questions
How do I open a TopoJSON file?
Drop it on this page or choose Peek a TopoJSON. Each of its objects opens as a layer on a map, with its features listed beside it.
How do I convert TopoJSON to GeoJSON?
Open it, choose Export, then Save the features as GeoJSON. Every shape comes back whole, with its properties.
Why do the borders look blocky up close?
A TopoJSON quantized coarsely keeps fewer places for its borders, which shows when you zoom in. That is in the file itself.
Does a .json file open as a map?
Yes, when its top object says it's a Topology or a FeatureCollection. Other JSON opens in the data viewer.