Convert GML to 12DA

Turn Geography Markup Language data into 12d Model archive — free, instant, and entirely in your browser, with optional reprojection to any of 200+ coordinate systems.

No upload. No account. Your data stays on your machine.

Drop your files here or click to browse.

Shapefile (all parts or .zip), GeoJSON, KML/KMZ, GPKG, GPX, DXF, 12d .12da, CSV, TAB and more — files never leave your browser.

Output format

Output coordinate system (optional)

Source CRS override (for CAD/CSV without one)

About Geography Markup Language (GML)

The OGC XML standard used by government cadastres and INSPIRE datasets across Europe.

Worth knowing: Schema-heavy; application schemas may need the companion .xsd.

About 12d Model archive (12DA)

12d Model's ASCII archive — the native exchange format of 12d, widely used in civil design and construction surveying. Reproj reads super strings, points and TIN surfaces, and writes attributed super strings that 12d can inquire — so GIS attributes survive the trip into 12d.

Worth knowing: Like CAD files, a .12da carries no coordinate system — tell us the grid when reading, and pick a projected grid (e.g. your MGA zone) when writing. Alignments are not converted yet. Very large TINs (over 300,000 triangles) are skipped in the browser; TINs are written as triangle strings, not as a 12d TIN.

How the conversion works

Drop your GML file above.
We read it locally with GDAL compiled to WebAssembly — nothing is uploaded.
Optionally pick an output coordinate system; official datum grids are applied automatically.
Download your 12DA result, with a transformation report showing exactly what was done.