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