metrics_echo: Number and proportion of points by echo types

In ptompalski/lidRmetrics: Point cloud metrics for the lidR package.

Number and proportion of points by echo types

Description

Based on the return number and number of returns, point cloud returns are classified into different echo types. Two different classification routines are applied. Under the first classification routine returns are classified into First, Intermediate, and Last. Under the second classification routine returns are classified into Single or Multiple. Function then calculates point counts and proportions by each echo type. Ratios of Last to First, Intermediate to First, and Multiple to Single, are also calculated.

Usage

metrics_echo(ReturnNumber, NumberOfReturns, z = NULL, zmin = NA)

.metrics_echo

Arguments

ReturnNumber	return number
NumberOfReturns	number of returns
z	Z coordinate of the point cloud (point heights)
zmin	numeric. Minimum z value. If set, z values (heights) below are ignored in calculations.

Format

An object of class formula of length 2.

Value

A list. Calculated metrics include:

• Number of first (n_first), intermediate (n_intermediate), last (n_last), single (n_single), and multiple (n_multiple) returns

• Proportion of first (p_first), intermediate (p_intermediate), last (p_last), single (p_single), and multiple (p_multiple) returns

• Ratio of Last to First (ratio_last_first), Intermediate to First (ratio_intermediate_first), and Multiple to Single (ratio_multiple_single).

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_echo(ReturnNumber=ReturnNumber, NumberOfReturns=NumberOfReturns))

m2 <- pixel_metrics(las, ~metrics_echo(ReturnNumber=ReturnNumber, NumberOfReturns=NumberOfReturns), res = 20)

ptompalski/lidRmetrics documentation built on May 7, 2024, 2:58 p.m.