Convert TopoJSON to GML

Convert TopoJSON (.topojson, .json) to GML (.gml) online for free. Fast, accurate geospatial format conversion with CRS reprojection.

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Upload your TopoJSON file and get GML output in seconds.

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About TopoJSON

TopoJSON is an extension of GeoJSON that encodes topology, eliminating redundancy and reducing file size. Shared boundaries between features are stored only once.

Extensions: .topojson, .json

Software: D3.js, Mapbox, QGIS, GDAL/OGR, Leaflet

Limitations: Read-only in most GIS software. Requires conversion for editing. Less widely supported than GeoJSON.

About GML

Geography Markup Language (GML) is an OGC XML-based format for expressing geographic features. It is often used for data exchange between government agencies and in INSPIRE-compliant systems.

Extensions: .gml

Software: QGIS, ArcGIS, GeoServer, Deegree, GDAL/OGR

Limitations: Verbose XML format — large file sizes. Complex schema definitions. Slower to read/write than binary formats.

How to Convert TopoJSON to GML

Upload your TopoJSON file (.topojson, .json)
Review detected layers, features, and coordinate system
Select GML as your output format
Choose a target coordinate reference system (optional)
Click Convert and download your GML file

Frequently Asked Questions

How do I convert TopoJSON to GML?

Upload your TopoJSON file to ConvertGeoData, review the detected data, select GML as the output format, and click Convert. Your converted file will be ready to download in seconds.

Is the TopoJSON to GML conversion free?

Yes! ConvertGeoData offers free conversions for all users. No account required for basic conversions. Sign up for a Pro or Business plan for higher limits.

Can I change the coordinate system during conversion?

Yes. ConvertGeoData automatically detects your source CRS and lets you reproject to any EPSG coordinate reference system during conversion.

What software can open GML files?

GML files can be opened with QGIS, ArcGIS, GeoServer, Deegree and more.