Why parcel area and measured field area can differ
The cadastral parcel area and the measured field area may not match, and that does not always mean a simple mistake.
Field takeaways
- Cadastral boundary and occupied boundary may differ.
- Phone GPS can shift area measurements.
- Wrong CRS transformation can move parcel lines.
- Noisy or unclosed polygons change area.
- Store the boundary source with the MapLab Survey result.
Where the difference comes from
Registered area, area computed from a cadastral drawing and area measured on the ground are three separate figures. Each carries the accuracy of the method that produced it.
Phone GPS sets a floor
With a few metres of uncertainty on each corner, a small parcel can vary by several per cent. On a narrow plot the relative error is worst, because the boundary is mostly corners.
Check before you conclude
Re-measure on a different day, in better sky conditions, and compare. A single measurement is not evidence of a discrepancy.
What settles it
Only a licensed cadastral survey can determine the legal boundary. Everything else describes what is currently on the ground.
Try these steps on your own phone.
MapLab Survey handles RTK/GNSS point capture, drawing, area and volume calculations and coordinate conversion, then exports to DXF, KML/KMZ, GeoJSON, Shapefile, GeoPackage, NCZ or CSV. Capture, calculation and export work offline. Live NTRIP corrections and online basemaps need a connection.
Frequently asked questions
Why does parcel area differ?
Boundary source, GPS, CRS and drawing method can differ.
Which one is official?
Authorized cadastral data and process.
Can MapLab Survey measure parcel area?
As reference or approximate field measurement.
How should I report the difference?
With source, method, CRS and accuracy note.
Technical references
The field guidance in this article is aligned with the technical and official references below.
Related: Field area calculation · Finding parcel corners · Parcel query on phone · MapLab Survey