Table 4.

Definitions of metaproperties

Name	Type	Definition	Pulse subset
Mean distance	Pulse	Mean distance to first returns	Above optical plane (≤90° zenith angle)
Mean intensity		Mean intensity of first returns
1st:2nd returns		Ratio of first to second returns
No return:pulses	Spatial	Ratio of the number of pulses with no returns, to total pulses emitted	Zenith angle range 30°–35°
Optical plane area (OPA)		Area of the polygon defined by joining the two‐dimensional (X and Y) Cartesian co‐ordinates of first returns from pulses emitted at the optical plane.	Optical plane (=90° zenith angle)
Rugosity		Ratio of the area of Delaunay triangulated surfaces (Lee & Schachter, 1980) fitted to the X, Y and Z co‐ordinates of returns, to the area of the polygon defined by the two‐dimensional (X and Y) Cartesian co‐ordinates of returns.	Zenith angle range 0°–30°, First returns.