100% local — files never leave your device
Convert GML to TopoJSON
Turn GML 3.2 into TopoJSON instantly in your browser. No upload, no account, and no file ever crosses the network.
About GML 3.2
OGC Geography Markup Language, the payload of many WFS services.
- Reader handles simple feature members; complex schemas may need a desktop GIS.
About TopoJSON
Quantized topology used by D3 and web cartography.
- Export quantizes coordinates and writes one arc per ring; arcs are not deduplicated.
Step by step
How to convert GML to TopoJSON
- 01
Drop your .gml file
Open the converter and drop the GML 3.2 file — parsing happens locally in a Web Worker, so nothing is uploaded.
- 02
Choose TopoJSON as the output
Pick TopoJSON, reproject to any of 180+ coordinate systems if needed, trim attributes and preview the geometry on a map.
- 03
Download the .topojson file
Save a single file, or convert a whole batch and download everything as a ZIP. Nothing is stored after the download.
GML to TopoJSON — questions
Is converting GML to TopoJSON really private?
Yes. The conversion runs entirely in your browser using a Web Worker — the GML 3.2 file is never sent to a server, so it works with confidential data and offline.
Do I need an account to convert GML to TopoJSON?
No. There is no signup, no email and no install. Open the converter, drop the file and download the result.
What happens to attributes and coordinate systems?
Export quantizes coordinates and writes one arc per ring; arcs are not deduplicated. You can also reproject between 180+ coordinate reference systems or add a custom proj4 definition before writing.
Need the other direction? Convert TopoJSON to GML