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Dispersion metrics

metrics_dispersion.Rd

Metrics characterizing the dispersion of point heights

Usage

metrics_dispersion(z, dz = 1, zmin = NA, zmax = NA)

.metrics_dispersion

Format

An object of class formula of length 2.

Arguments

z

Z coordinate of the point cloud (point heights)

dz

Numeric. Layer thickness to use when calculating entropy and VCI.

zmin

numeric. Minimum z value. If set, z values (heights) below are ignored in calculations.

zmax

Numeric. Maximum elevation for an entropy normalized to zmax.

Value

A list. Calculated metrics include:

  • ziqr interquartile distance

  • zMADmean mean absolute deviation (MAD) around the mean

  • zMADmedian mean absolute deviation (MAD) around the median

  • CRR canopy relief ratio

  • zentropy entropy

  • VCI vertical complexity index. Optional - calculated only if the zmax parameter is provided.

Details

When calculating zentropy and VCI, z values below 0 are removed.

Examples

library(lidR)
library(lidRmetrics)
LASfile <- system.file("extdata", "Megaplot.laz", package="lidR")
las <- readLAS(LASfile, select = "*", filter = "-keep_random_fraction 0.5")

m1 <- cloud_metrics(las, ~metrics_dispersion(z = Z))

m2 <- pixel_metrics(las, ~metrics_dispersion(z = Z, dz = 2, zmax = 30), res = 20)