Convert 12DA to GeoJSON
Turn 12d Model archive data into GeoJSON — 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.
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.
About GeoJSON (GeoJSON)
The web-native vector format — plain JSON, readable by every mapping library and most modern GIS tools. RFC 7946 expects WGS84 coordinates.
Worth knowing: Text-based and verbose for large datasets; RFC 7946 deprecates non-WGS84 CRS metadata.
How the conversion works
- Drop your 12DA 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 GeoJSON result, with a transformation report showing exactly what was done.