DXF has no coordinate system: which one should you choose?
A DXF contains drawing coordinates but no standard field that reliably identifies their coordinate reference system. The same pair of numbers could mean metres in a national grid, millimetres from a building corner or arbitrary drawing units. The person or system that created the drawing is the best source of that missing context.
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Three common cases in German project data
| Example coordinates | Likely case | What to use |
|---|---|---|
| 565432.12 / 5933210.45 | ETRS89 / UTM survey coordinates; zone 32 or 33 depending on the location and source documentation | EPSG:25832 or EPSG:25833 |
| 3565432.12 / 5935210.45 | DHDN / Gauss–Krüger; the leading digit indicates zone 3 | EPSG:31467 |
| 12.45 / 87.20 | Local construction origin, possibly expressed in metres or millimetres | No EPSG code until the drawing is georeferenced |
These ranges are regional clues, not a universal detector. A DXF from another country may use a completely different projected CRS.
How to identify the source system
- Ask the supplier. Check the delivery note, survey specification, project template or CAD drawing settings. Written source metadata takes precedence over a guess based on the location.
- Inspect a known point. Read the coordinate of a recognisable corner or marker and transform it with each plausible CRS. The correct interpretation should place it at the expected real-world location.
- Check the magnitude. In Germany, a six-digit easting and a northing around 5.2–6.1 million often indicate UTM. A seven-digit easting beginning with 2–5 may indicate a Gauss–Krüger zone. Small values often indicate a local origin.
- Check the drawing unit. A site plan may use millimetres. Scaling is a separate operation from assigning a CRS; confirm both before conversion.
Local construction coordinates need georeferencing
No EPSG code can turn a local origin into a real-world position. You need control points: locations identifiable both in the drawing and in a referenced dataset. Two points can determine a basic translation, rotation and scale; three or more provide a better check and expose a bad control point. Perform that georeferencing in suitable CAD or GIS software before treating the result as national-grid data.
Do not select UTM merely because the project is in Europe. A wrong assignment often produces valid-looking output without an error message, but the geometry will be in the wrong place.
What survives the CAD-to-GIS hand-off
DXF is drawing-oriented. CAD layers, colours and text may be exposed as fields by the reader, but they are not equivalent to a designed GIS attribute model. Blocks, curves, fills and presentation settings can require flattening or approximation. Review the layer list and geometry types in GeoVerto's analysis before starting a conversion.
DWG is a different, binary AutoCAD format and is not accepted by GeoVerto. Export it from the source CAD application as DXF first.