make_large_footprint_lidar_pulse: Scan a voxel forest with a virtual large footprint Lidar

In niknap/slidaRtools: Tools for lidar simulation and lidar processing

Scan a voxel forest with a virtual large footprint Lidar

Description

Function that simulates a Lidar waveform of a) a given voxel forest or b) a given lidar point cloud or CHM and returns a profile vector. The horizontal energy distribution inside the pulse is simulated with a Gaussian distribution.

Usage

make_large_footprint_lidar_pulse(
  xyz.dt,
  input = "vxf",
  Xctr,
  Yctr,
  diameter = 25,
  binwidth = 1,
  k = 0.2,
  sd = 0.5 * 12.5,
  VG.ratio = 2.5,
  weight.var = NA
)

Arguments

xyz.dt	Input data.table which can either be a) a voxel forest created with make.voxelforest function (containing columns X, Y, Z and LAI among others) or b) a discrete lidar point cloud or CHM (containing columns X, Y and Z)
input	Switch for the input type, which has to be either "vxf" for voxel forest or "lid" for discrete lidar data
Xctr	X-coordinate of the pulse center
Yctr	Y-coordinate of the pulse center
diameter	Diameter of the pulse footprint in meters (e.g. LVIS = 25 m, SLICER = 10 m, Icesat GLAS = 70 m, GEDI = 25 m)
binwidth	Vertical resolution of the waveform in meters
k	Extinction coefficient (only relevant if input = "vxf")
sd	Standard deviation of the Gaussian energy distribution (for a curve that approaches 0 at the margin of the pulse use sd = 0.4\*radius; for GEDI simulations commonly sd = 0.5\*radius is used, which leads to a more truncated energy distribution)
VG.ratio	Reflectance ratio between vegetation surface and ground surface
weight.var	Weighting variable, e.g. set to "Intensity" to use the intensity column in a lidar point cloud

Value

Vector of the Lidar waveform (normalized to a sum of 1)

Author(s)

Nikolai Knapp

Examples

in progress

niknap/slidaRtools documentation built on Oct. 16, 2024, 3:53 p.m.