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Process a LiDAR Point Cloud with Optional Transect Extraction

Source: R/clip_and_process_transect.R
process_point_cloud.Rd

This function provides a complete workflow for processing a LAS/LAZ file. It can perform decimation, interactive or automated transect extraction, height normalization, and tree segmentation. The key feature is its ability to define a transect area once and then clip it from both the original (unnormalized) and the fully processed point cloud.

Usage

process_point_cloud(
  las_file,
  normalize = TRUE,
  perform_treeID = FALSE,
  decimation = FALSE,
  extract_transect = TRUE,
  cs_width = 1,
  offset_x = 15,
  odir = NULL,
  oname = NULL
)

Arguments

las_file

A character string specifying the path to the LAS/LAZ file.

normalize

Logical. If TRUE, the point cloud is height-normalized using a TIN-based DTM. Ground classification should be present for best results. Default is TRUE.

perform_treeID

Logical. If TRUE, performs tree segmentation using lidR::silva2016 and merges the treeID into the point cloud. Default is FALSE.

decimation

Logical. If TRUE, decimates the point cloud to a resolution of one point per 0.5m voxel. Default is FALSE.

extract_transect

Logical. If TRUE, the user will be prompted to interactively draw the transect on a DTM plot. If FALSE, a transect is automatically created through the center of the point cloud. Default is TRUE.

cs_width

Numeric. The width of the transect in the same units as the LAS data. Default is 1.

offset_x

Numeric. If extract_transect = FALSE, this value specifies the start point's X-offset from the minimum X coordinate. Default is 15.

odir

Character string. The path to the output directory where processed files will be saved. If NULL, no files are written. Default is NULL.

oname

Character string. A base name for the output files. If NULL, "output" is used. Default is NULL.

Value

A list containing three LAS objects:

  • processed_cloud: The full point cloud after all processing steps.

  • processed_transect: The transect clipped from the fully processed cloud.

  • unnormalized_transect: The transect clipped from the cloud before normalization, retaining original Z values but including any initial classifications (hence the _class suffix when saved).

Examples

if (FALSE) { # \dontrun{
# Get the path to the example LAS file from lidR
las_file_in <- system.file("extdata", "Megaplot.laz", package = "lidR")

results <- process_point_cloud(
  las_file           = las_file_in,
  extract_transect   = FALSE, # Run automatically
  perform_treeID     = TRUE  # Skip tree identification
)

# The results are a list of LAS objects. We can plot them.
# Plot the final, processed transect (heights are normalized)
plot(results$processed_transect)

# To run interactively instead, simply use the default:
# results_interactive <- process_point_cloud(las_file = las_file_in)
} # }