Understand the scene
Transfer a column from a layer
Work on a light subsample, then project the answer (a classification, a segment id, a height) onto the full-resolution cloud, and leave a point with no source in range empty rather than guessing.
Transferring is free. Exporting the transferred column is Pro.
Part of Benchmarks.
When to use it
When a job was done on a decimated copy (for speed, or because the labels came from another tool) and the full cloud needs the result. Also to carry a column between two surveys of the same place once they are aligned.
Step by step
- Open the full-resolution cloud, then bring in the cloud that carries the column with File › Add Layer….
- Open Process › Transfer a column from a layer…. Under From, choose the source layer.
- Under Column, choose what to carry: a classification, a segment id, a height, any scalar.
- Under How, choose Nearest (the default), Majority (a vote of the neighbours, for classes) or Interpolate (a distance-weighted mean, for continuous values); the last two add a neighbours slider, 8 by default.
- Set the search radius in metres, or leave 0 to derive it from the point spacing.
- Leave Install as the scene’s classification ticked if the column is a classification (it is offered when there are at most 64 distinct values).
- Press Carry it across. The status reports how many points found a source; the rest get class 0 or no value.
What it was measured at
20 million points in 0.21 s. A class id is copied verbatim, never averaged.
From the command line
n3d-render-cli transfer --from subsample.las --to full.las --field classification --blend vote --out full_labelled.lasLimits, stated
- A point with no source within the radius gets nothing, not the nearest far-away value. A confident wrong answer is worse than an empty one.
- The two clouds must already be in the same frame. Align them first if they are not.
Related questions
What goes into a LAS export?
The class column fills LAS’s classification byte (0 to 255). Segment, instance and component ids are written as exact 32-bit unsigned extra bytes, and computed scalars such as height above ground or deviation as 32-bit floats, so PDAL, laspy and CloudCompare read them back. Intensity, returns, point source and scan angle keep their standard slots. The file is LAS 1.2 unless a class exceeds 31 or a coordinate system is present, in which case it is LAS 1.4.
More in the FAQ.
Related guides
confidence column, and split a powerline corridor into individual trees, spans and poles.
Understand the scene
Label components
A supervised review grid over the components in hand (primitives, segments or classes), with a brush per class, box and lasso in the view, a bulk selector by height, size and footprint, and a baseline so the model and the human can be compared.