Lidar QC Procedure

This page describes the procedure for the QC of the LIDAR data.

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QC Procedure

As it stands this is the Lidar data QC procedure. This could be improved and added to as time allows.

Remove noisy points

The first stage of the QC is to check the data and remove erroneous points. This can be done in Microstation/TerraSolid by creating a macro. It should be straightforward to script this into a GIS such as GRASS too.

In Terrascan goto Tools -> Macro

Press Add to add routines to the Macro.

• Any class to default class (Routine: by class)
• Remove groups of low points (Routine: low points)
• Remove single low points (Routine: low points)
• Remove isolated points (Routine: isolated points)

To run on large projects use "selected files" instead of reading all LAS files into memory. Check the result to see what points have been selected.

To delete the points: Point -> Delete -> by class

Can select/deselect points using the Add Point tool individually selecting points to get points which were missed by the classification algorithms.

To remove haze layers, use elevation to threshold (Routine: by absolute elevation). Select an elevation range whose minimum is well above any ground targets and maximum above the haze layer.