Delivery

Coordinate transformation control report: what to record for ED50, TUREF and WGS84 delivery

11 min read June 14, 2026

If you deliver transformed coordinates, final numbers are not enough. The receiver needs source datum, target EPSG, transformation method, control residuals and field notes.

Field takeaways

A transformation report should list source CRS, target CRS, EPSG code, units and vertical reference separately.
Control residuals are the most important part when ED50 source data is involved.
KML targets WGS84 geographic coordinates, while DXF often expects projected metre coordinates.
If residuals exceed tolerance, record the risk instead of hiding it.
Keep layers, notes, photos and exports together in MapLab Survey.

Why report the transformation?

When transformed data is delivered, the receiver needs to know the source CRS, target CRS, EPSG code, method and control residuals. Otherwise a clean-looking file can become a dispute later.

Minimum fields

Record source system, target system, transformation method, control residuals, vertical reference and risk notes. This is especially important for ED50 archive data.

Format-specific notes

KML usually targets WGS84 geographic coordinates. DXF often targets projected metre coordinates. CSV does not carry CRS by itself, so write the EPSG and units explicitly.

In the field · MapLab Survey

Measure, check and deliver in the right format.

MapLab Survey is a mobile field app for RTK/GNSS points, drawings, area/volume calculations, coordinate conversion and export to DXF, KML/KMZ, GeoJSON and CSV. Capture, calculation and export can work offline; live NTRIP corrections and online basemaps need connectivity.

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Frequently asked questions

Is a transformation report always mandatory?

Not always formally, but it is a strong professional delivery habit.

Should residuals be shown?

Yes. They define the limits of the delivered data.

What about CSV?

CSV does not carry CRS reliably, so include EPSG and units in notes.

Technical references

The field guidance in this article is aligned with the technical and official references below.