clouds_metrics {lidaRtRee}

Computes metrics on list of point clouds

Description

Computes metrics for a list of LAS objects (should be normalized point clouds). Calls the function cloud_metrics on each element and then arranges the results in a data.frame.

Usage

clouds_metrics(
  llasn,
  func = ~lidR::stdmetrics(X, Y, Z, Intensity, ReturnNumber, Classification, dz = 1)
)

Arguments

llasn

list of LAS objects

func

function. function applied on each element to compute metrics, default function is stdmetrics from package lidR

Value

A data frame with metrics in columns corresponding to LAS objects of the list (lines)

See Also

cloud_metrics, stdmetrics, aba_metrics, pixel_metrics

Examples

# load LAS file
LASfile <- system.file("extdata", "las_chablais3.laz", package="lidaRtRee")
las_chablais3 <- lidR::readLAS(LASfile)
# set projection
lidR::projection(las_chablais3) <- 2154

# extract four point clouds from LAS object
llas <- list()
llas[["A"]] <- lidR::clip_circle(las_chablais3, 974350, 6581680, 10)
llas[["B"]] <- lidR::clip_circle(las_chablais3, 974390, 6581680, 10)
llas[["C"]] <- lidR::clip_circle(las_chablais3, 974350, 6581640, 10)
# normalize point clouds
llas <- lapply(llas, function(x) {
  lidR::normalize_height(x, lidR::tin())
})

# compute metrics
clouds_metrics(llas)

# compute metrics with user-defined function
# mean and standard deviation of first return points above 10 m
user_func <- function(z, rn, hmin = 10) {
  # first return above hmin subset
  dummy <- which(z >= hmin & rn == 1)
  return(list(
    mean.z = mean(z[dummy]),
    sd.z = stats::sd(z[z > hmin])
  ))
}
clouds_metrics(llas, func = ~ user_func(Z, ReturnNumber, 10))