Check Points on Boundary Vertices

This is the survey-reconciliation check: corner points from a field survey are supposed to coincide with the vertices of the parcel boundary drawn from them. A point that has drifted — because the boundary was edited afterwards, or because the point was digitized separately — is an error you want to find before the plan is issued.

Every point is tested against the vertices of the polygon or line boundary; anything further away than the snapping tolerance is written to an error layer.

1. Load the boundary layer and the point layer.
2. Open KGA Topology > Check Points on Boundary Vertices.
3. Set the Snapping tolerance to match the precision of the survey — for a metric CRS, 0.001 is one millimetre.
4. Press Run. A message box reports the outcome.
5. Review the results with Open Error Inspector, which zooms to each error and can re-run this check once the points are moved.

• The tolerance is in the layer's map units. A projected CRS means metres and a geographic CRS means degrees — 0.001 degrees is about 110 m, which is not a tolerance, it is a free pass. Check the CRS before trusting a clean result.
• It tests against vertices, not against the boundary line. A point sitting exactly on a boundary segment, halfway between two vertices, is reported as an error. That is the intended behaviour for survey corners, and the wrong behaviour if you meant "on the line".
• The error layer is a memory layer; it disappears when the project closes unless you save it. Re-running replaces the previous one rather than stacking another beside it.
• The check is one-directional: it finds points with no vertex, not vertices with no point.