Compute summary metrics for individual LASfiles — get

get_summary() calculates standard summary metrics for LASfiles, including:

Usage

get_summary(
  path,
  out_dir = NULL,
  full.names = FALSE,
  samplebased = FALSE,
  zwbin = 10,
  iwbin = 100,
  metrics = c("t_min", "t_median", "t_max", "i_min", "i_mean", "i_median", "i_max",
    "i_p5", "i_p95", "i_sd", "z_min", "z_median", "z_max")
)

Arguments

path: Path to a LAS/LAZ/COPC file, a directory, or a Virtual Point Cloud (.vpc) file.
out_dir: Optional directory to save JSON summaries. If not set, the function returns a named list instead.
full.names: Logical. If TRUE, the returned list is named with full paths; otherwise, basenames are used.
samplebased: Logical. If TRUE, reads only a spatial subsample of each file (faster for large files).
zwbin: Numeric. Bin width (meters) for elevation histogram (z_histogram). Set 0 to skip z_histogram.
iwbin: Numeric. Bin width (intensity units) for intensity histogram (i_histogram). Set 0 to skip i_histogram.
metrics: Character vector of metrics to compute. Defaults to: c("t_min", "t_median", "t_max", "i_min", "i_mean", "i_median", "i_max", "i_p5", "i_p95", "i_sd", "z_min", "z_median", "z_max").

Value

If out_dir is not set, returns a named list, one element per LASfile. Each element is a list containing:

npoints: Total number of points
nsingle: Number of single-return points
nwithheld: Number of withheld points
nsynthetic: Number of synthetic points
npoints_per_return: Named vector of counts per return number
npoints_per_class: Named vector of counts per classification code
z_histogram: Elevation histogram (if zwbin > 0)
i_histogram: Intensity histogram (if iwbin > 0)
epsg: EPSG code of the LASfile CRS
metrics: List of calculated summary metrics, e.g., min, median, max for time, intensity, and elevation

If out_dir is set, the function returns NULL invisibly after writing JSON files.

Details

Temporal metrics (t_min, t_median, t_max)
Intensity metrics (i_min, i_mean, i_median, i_max, i_p5, i_p95, i_sd)
Elevation metrics (z_min, z_median, z_max)
Histograms (i_histogram, z_histogram) if iwbin and zwbin are greater than 0
Point counts and classifications (npoints, nsingle, nwithheld, nsynthetic, npoints_per_return, npoints_per_class)
Coordinate system (epsg)

Results can optionally be saved as JSON files per LASfile.

In comparison to lasR::summarise this function returns individual summaries per file instead of an aggregated summary among all files. If out_dir is provided, a JSON file is created for each LASfile, with the same name but .json extension. Existing JSON files are skipped automatically. If out_dir is not provided, the function returns a named list where each element corresponds to a LASfile.

Setting iwbin = 0 or zwbin = 0 disables calculation of intensity or elevation histograms, which can save time and memory for large datasets.

Parallel processing is used automatically for large numbers of files through map_las().

Examples

folder <- system.file("extdata", package = "managelidar")
las_files <- list.files(folder, full.names = T, pattern = "*20240327.laz")

las_files |> get_summary()
#> ERROR processing 3dm_32_547_5724_1_ni_20240327.laz: there is no package called ‘lasR’
#> ERROR processing 3dm_32_547_5725_1_ni_20240327.laz: there is no package called ‘lasR’
#> ERROR processing 3dm_32_548_5724_1_ni_20240327.laz: there is no package called ‘lasR’
#> ERROR processing 3dm_32_548_5725_1_ni_20240327.laz: there is no package called ‘lasR’
#> $`3dm_32_547_5724_1_ni_20240327.laz`
#> $`3dm_32_547_5724_1_ni_20240327.laz`$error
#> [1] "there is no package called ‘lasR’"
#> 
#> 
#> $`3dm_32_547_5725_1_ni_20240327.laz`
#> $`3dm_32_547_5725_1_ni_20240327.laz`$error
#> [1] "there is no package called ‘lasR’"
#> 
#> 
#> $`3dm_32_548_5724_1_ni_20240327.laz`
#> $`3dm_32_548_5724_1_ni_20240327.laz`$error
#> [1] "there is no package called ‘lasR’"
#> 
#> 
#> $`3dm_32_548_5725_1_ni_20240327.laz`
#> $`3dm_32_548_5725_1_ni_20240327.laz`$error
#> [1] "there is no package called ‘lasR’"
#> 
#>